Improved tools for qualified table names

• Specification of table names with schema/catalogs has been overhauled to
  make it simpler. This includes the following features and fixes:

  • The simplest way to refer to a qualified table is now to wrap it in
    I(), e.g. I("schema_name.table_name").

  • Use of sql() and ident_q() inside in_catalog() and in_schema()
    is once again supported (#1388).

  • It's ok to use ident_q() once again (#1413) and you should no longer
    see unsuppressable warnings about using in_schema() (#1408).

  • The names of the arguments to Id() no longer matter, only their order
    (#1416). Additionally, thanks to changes to the DBI package, you no
    longer need to name each argument.

  • If you accidentally pass a named vector to any of the database identifer
    functions, those names will be automatically stripped (#1404).

  • tbl_sql(check_from) is now deprecated.

• dbplyr now exports some tools to work with the internal table_path class
  which is useful for certain backends that need to work with this
  data structure (#1300).

Improved SQL

• New translations for clock functions add_years(), add_days(),
  date_build(), get_year(), get_month(), get_day(),
  and base::difftime() on SQL server, Redshift, Snowflake, and Postgres.

• select() will keep computed columns used to arrange() subqueries that are
  eliminated by a subsequent select (@ejneer, #1437).

• semi_join() will no longer inline away an aggregate filter (i.e. HAVING
  clause) that was followed by a select() (@ejneer, #1474)

• Improved function translations:

  • Functions qualified with the base namespace are now also translated, e.g.
    base::paste0(x, "_1") is now translated (@mgirlich, #1022).

  • -1 + x now generates a translation instead erroring (#1420).

  • x$name never attempts to evaluate name (#1368).

  • You can once again use NULL on the LHS of an infix operator in order
    to generate SQL with unusual syntax (#1345).

  • Namespaced calls now error if the function doesn't exist, or a translation
    is not available (#1426).

  • lead() translation coerces n to an integer.

• Databricks: now supports creating non-temporary tables too (#1418).

• Oracle:

  • db_explain() now works (@thomashulst, #1353).

  • as.Date() works when applied to a string (#1389).

  • head() is once again translated to FETCH FIRST. This does require Oracle
    12c or newer, but it actually works, compared to the approach using
    ROWNUM from #1292 (#1436).

  • Added support for str_replace() and str_replace_all() via
    REGEXP_REPLACE() (@thomashulst, #1402).

• Snowflake (@nathanhaigh, #1406)

  • Added support for str_starts() and str_ends() via REGEXP_INSTR()

  • Refactored str_detect() to use REGEXP_INSTR() so now supports
    regular expressions.

  • Refactored grepl() to use REGEXP_INSTR() so now supports
    case-insensitive matching through grepl(..., ignore.case = TRUE)

• SQL server:

  • Now products a clear error if you attempt to use n_distinct() in
    mutate() or filter() (#1366).

  • filter() does a better job of converting logical vectors
    from bit to boolean (@ejneer, #1288).

• MySQL: as.integer() gets correct translation (@krlmlr, #1375).

Minor improvements and bug fixes

• Deprecation status of functions deprecated in previous versions (at least
  2 years old) have been advanced. In particular, src_sql() is now defunct,
  as is the use of partial_eval() with character data.

• Database errors now show the generated SQL, which hopefully will make it
  faster to track down problems (#1401).

• When dbplyr creates an index on a table in a schema (e.g. schema.table),
  it now only includes the table name in the index name, not the schema name.

• The class of remote sources now includes all S4 class names, not just
  the first (#918).

• compute() passes additional arguments all the way to
  sql_query_save()-methods (@rsund).

• db_sql_render() correctly passes on ... when re-calling with
  sql_options set (#1394).

• reframe() now gives an informative error that it isn't supported (#1148).

• rows_patch(in_place = FALSE) now works when more than one column should be
  patched (@gorcha, #1443).

• New simulate_mariadb() (@krlmlr, #1375).

• sql_translator() now checks for duplicated definitions (@krlmlr, #1374).

Breaking changes

• Using compute(temporary = FALSE) without providing a name is now
  deprecated (@mgirlich, #1154).

• ntile()'s first argument has been renamed from order_by to x to
  match the interface of dplyr::ntile() (@mgirlich, #1242).

• simulate_vars() and simulate_vars_is_typed() were removed as they weren't
  used and tidyselect now offers tidyselect_data_proxy() and
  tidyselect_data_has_predicates() (@mgirllich, #1199).

• sql_not_supported() now expects a function name without parentheses.

• sql_query_append(), sql_query_insert(), sql_query_update(),
  sql_query_upsert(), and sql_query_delete() changed their arguments to
  make them more consistent to the other sql_query_*() functions:

  • x_name was renamed to table.
  • y was renamed to from and must now be a table identifier or SQL instead
    of a lazy table.
  • sql_query_append() and sql_query_insert() have gained the argument cols.

• remote_name() now returns a string with the name of the table. To get the
  qualified identifier use the newly added remote_table() (@mgirlich, #1280).

• tbl_lazy() loses src argument after it has been deprecated for years
  (@mgirlich, #1208).

• translate_sql() now requires the con argument (@mgirlich, #1311).
  The vars argument has been removed after it threw an error for the last 7
  years (@mgirlich).

Improved SQL

• Preliminary databricks Spark SQL backend (#1377).

• Joins

  • *_join() after full_join() works again (@mgirlich, #1178).

  • *_join() now allows specifying the relationship argument. It must be
    NULL or "many-to-many" (@bairdj, #1305).

  • Queries now qualify * with the table alias for better compatibility
    (@mgirlich, #1003).

  • full_join() can now handle column names that only differ in case
    (@ejneer, #1255).

  • The na_matches argument of semi_join() and anti_join() works again
    (@mgirlich, #1211).

  • A semi/anti_join() on fitlered y is inlined when possible (@mgirlich, #884).

  • Joins now work again for Pool and Oracle connections (@mgirlich, #1177, #1181).

• A sequence of union() resp. union_all() now produces a flat query
  instead of subqueries (@mgirlich, #1269).

• Added translations for:

  • nzchar() (@MichaelChirico, @mgirlich, #1094).
  • str_detect(), str_starts() and str_ends() with fixed patterns
    (@mgirlich, #1009).
  • runif() (@mgirlich, #1200).

• if_any() and if_all() translations are now wrapped in parentheses.
  This makes sure it can be combined via & with other conditions
  (@mgirlich, #1153).

• nth(), first(), and last() now support the na_rm argument
  (@mgirlich, #1193).

Minor improvements and bug fixes

• across() now supports namespaced functions, e.g.
  across(x, dplyr::dense_rank) (@mgirlich, #1231).

• db_copy_to(overwrite = TRUE) now actually works.

• db_copy_to()'s ... are now passed to db_write_table() (@mgirlich, #1237).

• Added db_supports_table_alias_with_as() to customise whether a backend
  supports specifying a table alias with AS or not (@mgirlich).

• db_write_table() and db_save_query() gain the overwrite argument.

• dbplyr_pivot_wider_spec() is now exported. Unlike pivot_wider() this can
  be lazy. Note that this will be removed soon after pivot_wider_spec()
  becomes a generic (@mgirlich).

• filter()ing with window functions now generates columns called col01
  rather than q01 (@mgirlich, #1258).

• pivot_wider() now matches tidyr NA column handling (@ejneer #1238).

• select() can once again be used after arrange(desc(x)) (@ejneer, #1240).

• show_query() and remote_query() gain the argument sql_options that allows
  to control how the SQL is generated. It can be created via sql_options()
  which has the following arguments:

  • cte: use common table expressions?
  • use_star: use SELECT * or explicitly select every column?
  • qualify_all_columns: qualify all columns in a join or only the ambiguous ones?
    (@mgirlich, #1146).

  Consequently the cte argument of show_query() and remote_query() has
  been deprecated (@mgirlich, #1146).

• slice_min/max() can now order by multiple variables like dplyr, e.g. use
  slice_min(lf, tibble(x, y)) (@mgirlich, #1167).

• slice_*() now supports the data masking pronouns .env and .data (@mgirlich, #1294).

• sql_join_suffix() gains the argument suffix so that methods can check
  whether the suffix is valid for the backend (@mgirlich).

• sql_random() is now deprecated. It was used to power slice_sample() which
  is now done via the translation for runif() (@mgirlich, #1200).

• tbl() now informs when the user probably forgot to wrap the table identifier
  with in_schema() or sql() (@mgirlich, #1287).

Backend specific improvements

• Access

  • Added translation for != to <> (@erikvona, #1219).

• DuckDB

  • now supports the returning argument of rows_*().

• MySQL/MariaDB:

  • rows_update() and rows_patch() now give an informative error when the
    unsupported returning argument is used (@mgirlich, #1279).
  • rows_upsert() now gives an informative error that it isn't supported
    (@mgirlich, #1279).
  • rows_*() use the column types of x when auto copying y (@mgirlich, #1327).
  • copy_inline() now works (@mgirlich, #1188).
  • Fix translation of as.numeric(), as.POSIXct(), as_datetime(), and
    as.integer64() (@avsdev-cw, #1189).

• MS SQL:

  • row_number() now works when no order is specified (@ejneer, @fh-mthomson, #1332)

• Oracle:

  • Fix translation of rows_upsert() (@mgirlich, @TBlackmore, #1286)
  • head(n) is now translated to WHERE ROWNUM <= n to also support old
    versions <= 11.2 (@JeremyPasco, #1292).

• Postgres

  • The rows_*() functions now also work inside a transaction (@mgirlich, #1183).

• SQLite

  • Subqueries now also get an alias. This makes it consistent with other
    backends and simplifies the implementation.

• SQL Server

  • distinct(.keep_all = TRUE) now works (@mgirlich, #1053).
  • The translation of between() now also works when used in mutate()
    (@mgirlich, #1241).
  • any() and all() now work (@ejneer, #1273).
  • Fixed negation of bit (boolean) fields (@ejneer, #1239)

• Snowflake:

  • na.rm = TRUE is now respected in pmin() and pmax() instead of being silently ignored (@fh-mthomson, #1329)
  • row_number() now works when no order is specified (@fh-mthomson, #1332)

• Teradata

  • distinct() + head() now work (@mgirlich, #685).
  • as.Date(x) is now translate to CAST(x AS DATE) again unless x is a
    string (@mgirlich, #1285).
  • row_number() no longer defaults to partitioning by groups (now aligned with other databases when no order is specified: ROW_NUMBER() defaults to ORDER BY (SELECT NULL)) (@fh-mthomson, #1331)

• Hot patch release to resolve R CMD check failures.

• Hot patch release to resolve R CMD check failures.

• Hot patch release to resolve R CMD check failures.

Breaking changes

• window_order() now only accepts bare symbols or symbols wrapped in desc().
  This breaking change is necessary to allow select() to drop and rename
  variables used in window_order() (@mgirlich, #1103).

Improved error messages

• quantile() and median() now error for SQL Server when used in summarise()
  and for PostgreSQL when used in mutate() as they can't be properly
  translated (@mgirlich, #1110).

• Added an informative error for unsupported join arguments unmatched and
  multiple (@mgirlich).

• Using predicates, e.g. where(is.integer), in across() now produces an
  error as they never worked anyway (@mgirlich, #1169).

• Catch unsupported argument pivot_wider(id_expand = TRUE) and
  pivot_longer(cols_vary) (@mgirlich, #1109).

Bug fixes in SQL generation

• Fixed an issue when using a window function after a summarise() and
  select() (@mgirlich, #1104).

• Fixed an issue when there where at least 3 joins and renamed variables
  (@mgirlich, #1101).

• mutate() and select() after distinct() now again produce a subquery to
  generate the correct translation (@mgirlich, #1119, #1141).

• Fixed an issue when using filter() on a summarised variable (@mgirlich, #1128).

• mutate() + filter() now again produces a new query if the mutate()
  uses a window function or SQL (@mgirlich, #1135).

• across() and pick() can be used (again) in distinct() (@mgirlich, #1125).

• The rows_*() function work again for tables in a schema in PostgreSQL
  (@mgirlich, #1133).

Minor improvements and bug fixes

• sql() now evaluates its arguments locally also when used in across() (@mgirlich, #1039).

• The rank functions (row_number(), min_rank(), rank(), dense_rank(),
  percent_rank(), and cume_dist()) now support multiple variables by
  wrapping them in tibble(), e.g. rank(tibble(x, y)) (@mgirlich, #1118).

• pull() now supports the argument name (@mgirlich, #1136).

• Added support for join_by() added in dplyr 1.1.0 (@mgirlich, #1074).

• Using by = character() to perform a cross join is now soft-deprecated in
  favor of cross_join().

• full_join() and right_join() are now translated directly to FULL JOIN
  and RIGHT JOIN for SQLite as native support was finally added (@mgirlich, #1150).

• case_match() now works with strings on the left hand side (@mgirlich, #1143).

• The rank functions (row_number(), min_rank(), rank(), dense_rank(),
  percent_rank(), and cume_dist()) now work again for variables wrapped in
  desc(), e.g. row_number(desc(x)) (@mgirlich, #1118).

• Moved argument auto_index after ... in *_join() (@mgirlich, #1115).

• Removed dependency on assertthat (@mgirlich, #1112).

• across() now uses the original value when a column is overriden to match
  the behaviour of dplyr. For example mutate(df, across(c(x, y), ~ .x / x))
  now produces

  SELECT `x` / `x` AS `x`, `y` / `x` AS `y`
  FROM `df`
  

  instead of

  SELECT `x`, `y` / `x` AS `y`
  FROM (
    SELECT `x` / `x` AS `x`, `y`
    FROM `df`
  ) 
  

  (@mgirlich, #1015).

• Restricted length of table aliases to avoid truncation on certain backends (e.g., Postgres) (@fh-mthomson, #1096)

• Compatibility with purrr 1.0.0 (@mgirlich, #1085).

New features

• stringr::str_like() (new in 1.5.0) is translated to the closest LIKE
  equivalent (@rjpat, #509)

• In preparation for dplyr 1.1.0:

  • The .by argument is supported (@mgirlich, #1051).
  • Passing ... to across() is deprecated because the evaluation timing
    of ... is ambiguous. Now instead of (e.g.)
    across(a:b, mean, na.rm = TRUE) use
  • pick() is translated (@mgirlich, #1044).
  • case_match() is translated (@mgirlich, #1020).
  • case_when() now supports the .default argument (@mgirlich, #1017).

• Variables that aren't found in either the data or in the environment now
  produce an error (@mgirlich, #907).

SQL optimisation

• dbplyr now produces fewer subqueries resulting in shorter, more readable, and,
  in some cases, faster SQL. The following combination of verbs now avoids a
  subquery if possible:

  • *_join() + select() (@mgirlich, #876).
  • select() + *_join() (@mgirlich, #875).
  • mutate() + filter() and filter() + filter() (@mgirlich, #792).
  • distinct() (@mgirlich, #880).
  • summarise() + filter() now translates to HAVING (@mgirlich, #877).
  • left/inner_join() + left/inner_join() (@mgirlich, #865).

• dbplyr now uses SELECT * after a join instead of explicitly selecting every
  column, where possible (@mgirlich, #898).

• Joins only use the table aliases ("LHS" and "RHS") if necessary (@mgirlich).

• When using common table expressions, the results of joins and set operations
  are now reused (@mgirlich, #978).

Improved error messages

• Many errors have been improved and now show the function where the error
  happened instead of a helper function (@mgirlich, #907).

• Errors produced by the database, e.g. in collect() or rows_*(), now show
  the verb where the error happened (@mgirlich).

• window_order() now produces a better error message when applied to a data
  frame (@mgirlich, #947).

• Using a named across() now gives a clear error message (@mgirlich, #761).

Minor improvements and bug fixes

• Keyword highlighting can now be customised via the option dbplyr_highlight.
  Turn it off via options(dbplyr_highlight = FALSE) or pass a custom ansi
  style, e.g. options(dbplyr_highlight = cli::combine_ansi_styles("bold", "cyan"))
  (@mgirlich, #974).

• The rank functions (row_number(), min_rank(), rank(), dense_rank(),
  percent_rank(), and cume_dist()) now give missing values the rank NA to
  match the behaviour of dplyr (@mgirlich, #991).

• NAs in blob()s are correctly translated to NULL (#983).

• copy_inline() gains a types argument to specify the SQL column types
  (@mgirlich, #963).

• cur_column() is now supported (@mgirlich, #951).

• distinct() returns columns ordered the way you request, not the same
  as the input data (@mgirlich).

• fill() can now fill "downup" and "updown" (@mgirlich, #1057), and
  now order by non-numeric columns also in the up direction (@mgirlich, #1057).

• filter() now works when using a window function and an external vector
  (#1048).

• group_by() + renamed columns works once again (@mgirlich, #928).

• last() is correctly translated when no window frame is specified
  (@mgirlich, #1063).

• setOldClass() uses a namespace, fixing an installation issue (@mgirlich, #927).

• sql() is now translated differently. The ... are now evaluated locally
  instead of being translated with translate_sql() (@mgirlich, #952).

Backend specific improvements

• HANA:

  • Correctly translates as.character() (#1027).
  • copy_inline() now works for Hana (#950)

• MySQL:

  • str_flatten() uses collapse = "" by default (@fh-afrachioni, #993)

• Oracle:

  • slice_sample() now works for Oracle (@mgirlich, #986).
  • copy_inline() now works for Oracle (#972)

• PostgreSQL:

  • Generates correct literals for Dates (#727).
  • str_flatten() uses collapse = "" by default (@fh-afrachioni, #993)
  • rows_*() use the column types of x when auto copying (@mgirlich, #909).

• Redshift:

  • round() now respects the digits argument (@owenjonesuob, #1033).
  • No longer tries to use named windows anymore (@owenjonesuob, #1035).
  • copy_inline() now works for Redshift (#949, thanks to @ejneer for an
    initial implementation).
  • str_flatten() uses collapse = "" by default (@fh-afrachioni, #993)

• Snowflake:

• numeric functions: all(), any(), log10(), round(), cor(), cov()
  and sd().

• date functions: day(), mday(), wday(), yday(), week(),
  isoweek(), month(), quarter(), isoyear(), seconds(), minutes(),
  hours(), days(), weeks(), months(), years() and floor_date().

• string functions: grepl(), paste(), paste0(), str_c(), str_locate(),
  str_detect(), str_replace(), str_replace_all(), str_remove(),
  str_remove_all(), str_trim(), str_squish() and str_flatten()
  (@fh-afrachioni, #860).

• str_flatten() uses collapse = "" by default (@fh-afrachioni, #993)

• SQLite:

  • quantile() gives a better error saying that it is not supported
    (@mgirlich, #1000).

• SQL server:

  • as.POSIXct() now translated correctly (@krlmlr, #1011).
  • median() now translated correctly (#1008).
  • pivot_wider() works again for MS SQL (@mgirlich, #929).
  • Always use 1 and 0 as literals for logicals (@krlmlr, #934).

• Teradata:

  • Querying works again. Unfortunately, the fix requires every column to
    once again by explicitly selected (@mgirlich, #966).
  • New translations for as.Date(), week(), quarter(), paste(),
    startsWith(), row_number(), weighted.mean(), lead(), lag(), and
    cumsum() (@overmar, #913).

• Querying Oracle databases works again. Unfortunately, the fix requires every
  column to be explicitly selected again (@mgirlich, #908).

• semi_join() and anti_join() work again for Spark (@mgirlich, #915).

• str_c() is now translated to || in Oracle (@mgirlich, #921).

• sd(), var(), cor() and cov() now give clear error messages on
  databases that don't support them.

• any() and all() gain default translations for all backends.

dbplyr 2.2.0

New features

• SQL formatting has been considerably improved with new wrapping and indenting.
  show_query() creates more readable queries by printing the keywords in blue
  (@mgirlich, #644). When possible dbplyr now uses SELECT * instead of
  explicitly selecting every column (@mgirlich).

• Added support for rows_insert(), rows_append(), rows_update(),
  rows_patch(), rows_upsert(), and rows_delete() (@mgirlich, #736).

• Added copy_inline() as a copy_to() equivalent that does not need write
  access (@mgirlich, #628).

• remote_query(), show_query(), compute() and collect() have an
  experimental cte argument. If TRUE the SQL query will use common table
  expressions instead of nested queries (@mgirlich, #638).

• New in_catalog(), which works like in_schema(), but allows creation of
  table identifiers consisting of three components: catalog, schema, name
  (#806, @krlmlr).

Improvements to SQL generation

• When possible, dbplyr now uses SELECT * instead of explicitly selecting
  every column (@mgirlich).

• New translation for cut() (@mgirlich, #697).

• Improved translations for specific backends:

  • as.Date() for Oracle (@mgirlich, #661).
  • case_when() with a final clause of the form TRUE ~ ... uses ELSE ...
    for SQLite (@mgirlich, #754).
  • day(), week(), isoweek(), and isoyear() for Postgres (@mgirlich, #675).
  • explain() for ROracle (@mgirlich).
  • fill() for SQL Server (#651, @mgirlich) and RPostgreSQL (@mgirlich).
  • quantile() for SQL Server (@mgirlich, #620).
  • str_flatten() for Redshift (@hdplsa, #804)
  • slice_sample() for MySQL/MariaDB and SQL Server (@mgirlich, #617).
  • union() for Hive (@mgirlich, #663).

• The backend function dbplyr_fill0() (used for databases that lack
  IGNORE NULLS support) now respects database specific translations
  (@rsund, #753).

• Calls of the form stringr::foo() or lubridate::foo() are now evaluated in
  the database, rather than locally (#197).

• Unary plus (e.g. db %>% filter(x == +1)) now works (@mgirlich, #674).

• is.na(), ifelse(), if_else(), case_when(), and if()
  generate slightly more compact SQL (@mgirlich, #738).

• if_else() now supports the missing argument (@mgirlich, #641).

• n() now respects the window frame (@mgirlich, #700).

• quantile() no longer errors when using the na.rm argument (@mgirlich, #600).

• remote_name() now returns a name in more cases where it makes sense
  (@mgirlich, #850).

• The partial evaluation code is now more aligned with dtplyr. This makes it
  easier to transfer bug fixes and new features from one package to the other.
  In this process the second argument of partial_eval() was changed to a lazy
  frame instead of a character vector of variables (@mgirlich, #766).
  Partially evaluated expressions with infix operations are now correctly
  translated. For example translate_sql(!!expr(2 - 1) * x) now works
  (@mgirlich, #634).

Minor improvements and bug fixes

• New pillar::tbl_format_header() method for lazy tables: Printing a lazy
  table where all rows are displayed also shows the exact number of rows in the
  header. The threshold is controlled by getOption("pillar.print_min"),
  with a default of 10 (#796, @krlmlr).

• The 1st edition extension mechanism is formally deprecated (#507).

• across(), if_any() and if_all() now defaults to .cols = everything()
  (@mgirlich, #760). If .fns is not provided if_any() and if_all() work
  like a parallel version of any()/any() (@mgirlich, #734).

• across(), if_any(), and if_all() can now translate evaluated lists
  and functions (@mgirlich, #796), and accept the name of a list of functions
  (@mgirlich, #817).

• Multiple across() calls in mutate() and transmute() can now access
  freshly created variables (@mgirlich, #802).

• add_count() now doesn't change the groups of the input (@mgirlich, #614).

• compute() can now handle when name is named by unnaming it first
  (@mgirlich, #623), and now works when temporary = TRUE for Oracle
  (@mgirlich, #621).

• distinct() now supports .keep_all = TRUE (@mgirlich, #756).

• expand() now works in DuckDB (@mgirlich, #712).

• explain() passes ... to methods (@mgirlich, #783), and
  works for Redshift (@mgirlich, #740).

• filter() throws an error if you supply a named argument (@mgirlich, #764).

• Joins disambiguates columns that only differ in case (@mgirlich, #702).
  New arguments x_as and y_as allow you to control the table alias
  used in SQL query (@mgirlich, #637). Joins with na_matches = "na" now work
  for DuckDB (@mgirlich, #704).

• mutate() and transmute() use named windows if a window definition is
  used at least twice and the backend supports named windows (@mgirlich, #624).

• mutate() now supports the arguments .keep, .before, and .after
  (@mgirlich, #802).

• na.rm = FALSE only warns once every 8 hours across all functions (#899).

• nesting() now supports the .name_repair argument (@mgirlich, #654).

• pivot_longer() can now pivot a column named name (@mgirlich, #692),
  can repair names (@mgirlich, #694), and can work with multiple names_from
  columns (@mgirlich, #693).

• pivot_wider(values_fn = ) and pivot_longer(values_transform = )
  can now be formulas (@mgirlich, #745).

• pivot_wider() now supports the arguments names_vary, names_expand, and
  unused_fn (@mgirlich, #774).

• remote_name() now returns a name in more cases where it makes sense
  (@mgirlich, #850).

• sql_random() is now exported.

• ungroup() removes variables in ... from grouping (@mgirlich, #689).

• transmute() now keeps grouping variables (@mgirlich, #802).

• New support for Snowflake (@edgararuiz)

• compute(), sql_table_index(), and sql_query_wrap() now work with
  schemas (@mgirlich, #595).

• if_any() and if_all() are now translated.

• group_by() now ungroups when the dots argument is empty and .add is FALSE
  (@mgirlich, #615).

• sql_escape_date() and sql_escape_datetime gain methods for MS Access
  (@erikvona, #608).

New features

• Thanks to @mgirlich, dbplyr gains support for key verbs from tidyr:
  pivot_longer() (#532), pivot_wider() (#543), expand() (#538),
  complete() (#538), replace_na() (#538), fill() (#566).

• @mgirlich is now a dbplyr author in recognition of his significant and
  sustained contributions.

• across() implementation has been rewritten to support more inputs:
  it now translates formulas (#525), works with SQL functions that don't have
  R translations (#534), and work with NULL (#554)

• summarise() now supports argument .groups (@mgirlich, #584).

SQL translation

• All backends: str_sub(), substr() and substring() get better
  translations (#577). Most importantly, the results of using negative
  locations should match the underlying R implementations more closely.

• MS SQL:

  • as.integer() and as.integer64() translations cast first to NUMERIC
    to avoid CASTing weirdness (@DavidPatShuiFong, #496).

  • Assumes a boolean context inside of [ (#546)

  • str_sub() with end = -1 now works (#577).

• Redshift: lag() and lead() lose the default parameter since it's
  not supported (@hdplsa, #548).

• SQLite: custom translation of full_join() and right_join()
  (@mgirlich, #536).

Minor improvements and bug fixes

• RPostgreSQL backend warns if temporary = TRUE since temporary tables are
  not supported by RPostgres::dbWriteTable() (#574).

• count() method provides closer match to dplyr semantics (#347).

• distinct() now respects grouping (@mgirlich, #535).

• db_connection_describe() no longer uses partial matching (@mgirlich, #564).

• pull() no longer select()s the result when there's already only
  one variable (#562).

• select() no longer relocates grouping variables to the front
  (@mgirlich, #568). and informs when adding missing grouping variables
  (@mgirlich, #559).

• tbl.src_dbi(...) now passed on to tbl_sql() (#530).

(To become dbplyr 2.0.0)

dplyr 1.0.0 compatibility

• across() is now translated into individual SQL statements (#480).

• rename() and select() support dplyr 1.0.0 tidyselect syntax (apart from
  predicate functions which can't easily work on computed queries) (#502).

• relocate() makes it easy to move columns (#494) and rename_with() makes
  it easy to rename columns programmatically (#502).

• slice_min(), slice_max(), and slice_order() are now supported.
  slice_head() and slice_tail() throw clear error messages (#394)

SQL generation

• Documentation has been radically improved with new topics for each major
  verb and each backend giving more details about the SQL translation.

• intersect(), union() and setdiff() gain an all argument to add the
  ALL argument (#414).

• Join functions gains a na_matches argument that allows you to control
  whether or not NA (NULL) values match other NA values. The default is
  "never", which is the usual behaviour in databases. You can set
  na_matches = "na" to match R's usual join behaviour (#180). Additional
  arguments error (instead of being silently swallowed) (#382).

• Joins now only use aliases where needed to disambiguate columns; this should
  make generated queries more readable.

• Subqueries no longer include an ORDER BY clause. This is not part of the
  SQL spec, and has very limited support across databases. Now such queries
  generate a warning suggesting that you move your arrange() call later in
  the pipeline (#276). (There's one exception: ORDER BY is still generated
  if LIMIT is present; this tends to affect the returns rows but not
  necessarily their order).

• Subquery names are now scoped within the query. This makes query text
  deterministic which helps some query optimisers/cachers (#336).

• sql_optimise() now can partially optimise a pipeline; due to an unfortunate
  bug it previously gave up too easily.

• in_schema() quotes each input individually (#287) (use sql() to opt out
  of quoting, if needed). And DBI::Id() should work anywhere that
  in_schema() does.

SQL translation

• Experimental new SAP HANA backend (#233). Requires the latest version of odbc.

• All backends:

  • You can now use :: in translations, so that (e.g.) dbplyr::n() is
    translated to count(*) (#207).

  • [[ can now also translate numeric indices (#520).

  • %/% now generates a clear error message; previously it was translated to
    / which is not correct (#108).

  • n() is translated to count(*) instead of count() (#343).

  • sub_str() translation is more consistent in edge cases (@ianmcook).

  • All median() (@lorenzwalthert, #483), pmin(), pmax() (#479), sd()
    and var() functions have an na.rm argument that warns once when not
    TRUE. This makes them consistent with mean() and sum().

  • substring() is now translated the same way as substr() (#378).

• blob vectors can now be used with !! and
  !!! operators, for example in filter() (@okhoma, #433)

• MySQL uses standard SQL for index creation.

• MS SQL translation does better a distinguishing between bit and boolean
  (#377, #318). if and ifelse once again generate IIF, creating
  simpler expressions. as.*() function uses TRY_CAST() instead
  of CAST() for version 11+ (2012+) (@DavidPatShuiFong, #380).

• odbc no longer translates count(); this was an accidental inclusion.

• Oracle translation now depends on Oracle 12c, and uses a "row-limiting"
  clause for head(). It gains translations for today() and now(), and
  improved as.Date() translation (@rlh1994, #267).

• PostgreSQL: new translations for lubridate period functions years(),
  months(), days(), and floor_date() (@bkkkk, #333) and stringr functions
  str_squish(), str_remove(), and str_remove_all() (@shosaco).

• New RedShift translations when used with RPostgres::Redshift().

  • str_replace() errors since there's no Redshift translation,
    and str_replace_all() uses REGEXP_REPLACE() (#446).

  • paste() and paste0() use || (#458).

  • as.numeric() and as.double() cast to FLOAT (#408).

  • substr() and str_sub() use SUBSTRING() (#327).

• SQLite gains translations for lubridate functions today(), now(),
  year(), month(), day(), hour(), minute(), second(),yday()
  (#262), and correct translation for median() (#357).

Extensibility

If you are the author of a dbplyr backend, please see vignette("backend-2") for details.

• New dbplyr_edition() generic allows you to opt-in to the 2nd edition of
  the dbplyr API.

• db_write_table() now calls DBI::dbWriteTable() instead of nine generics
  that formerly each did a small part: db_create_indexes(), db_begin(),
  db_rollback(), db_commit(), db_list_tables(), drop_drop_table(),
  db_has_table(), db_create_table(), and db_data_types(). You can
  now delete the methods for these generics.

  db_query_rows() is no longer used; it appears that it hasn't been used
  for some time, so if you have a method, you can delete it.

• DBI::dbQuoteIdentifier() is now used instead of sql_escape_ident() and
  DBI::dbQuoteString() instead of sql_escape_string().

• A number of db_* generics have been replaced with new SQL generation
  generics:

  • dplyr::db_analyze() -> dbplyr::sql_table_analyze()
  • dplyr::db_create_index() -> dbplyr::sql_table_index()
  • dplyr::db_explain() -> dbplyr::sql_queriy_explain()
  • dplyr::db_query_fields() -> dbplyr::sql_query_fields()
  • dplyr::db_save_query() -> dbplyr::sql_query_save()

  This makes them easier to test and is an important part of the process of
  moving all database generics in dbplyr (#284).

• A number of other generics have been renamed to facilitate the move from
  dplyr to dbplyr:

  • dplyr::sql_select() -> dbplyr::sql_query_select()
  • dplyr::sql_join() -> dbplyr::sql_query_join()
  • dplyr::sql_semi_join() -> dbplyr::sql_query_semi_join()
  • dplyr::sql_set_op() -> dbplyr::sql_query_set_op()
  • dplyr::sql_subquery() -> dbplyr::sql_query_wrap()
  • dplyr::db_desc() -> dbplyr::db_connection_describe()

• New db_temporary_table() generic makes it easier to work with databases
  that require temporary tables to be specially named.

• New sql_expr_matches() generic allows databases to use more efficient
  alternatives when determine if two values "match" (i.e. like equality but
  a pair of NULLs will also match). For more details, see
  https://modern-sql.com/feature/is-distinct-from

• New sql_join_suffix() allows backends to control the default suffixes
  used (#254).

Minor improvements and bug fixes

• All old lazy eval shims have been removed. These have been deprecated for
  some time.

• Date-time escaping methods for Athena and Presto have moved to the packages
  where they belong.

• Attempting to embed a Shiny reactive in a query now gives a helpful error
  (#439).

• copy_lahman() and copy_nycflights13() (and hence nycflights13_sqlite())
  and friends now return DBI connections rather than the now deprecated
  src_dbi() (#440).

• copy_to() can now overwrite when table is specified with schema (#489),
  and gains an in_transaction argument used to optionally suppress the
  transaction wrapper (#368).

• distinct() no longer duplicates column if grouped (#354).

• transmute() now correctly tracks variables it needs when creating
  subqueries (#313).

• mutate() grouping variables no longer generates a downstream error (#396)

• mutate() correctly generates subqueries when you re-use the same variable
  three or more times (#412).

• window_order() overrides ordering, rather than appending to it.

• Internally DBI::dbExecute() now uses immediate = TRUE; this improves
  support for session-scoped temporary tables in MS SQL (@krlmlr, #438).

• Subqueries with ORDER BY use TOP 9223372036854775807 instead of
  TOP 100 PERCENT on SQL Server for compatibility with Azure Data Warehouse
  (#337, @alexkyllo).

• escape() now supports blob vectors using new sql_escape_raw()
  generic. It enables using blob variables in
  dplyr verbs, for example to filter nvarchar values by UTF-16 blobs
  (see https://github.com/r-dbi/DBI/issues/215#issuecomment-356376133).
  (@okhoma, #433)

• Added setOldClass() calls for "ident" and "ident_q" classes for
  compatibility with dplyr 1.0.0 (#448, @krlmlr).

• Postgres str_detect() translation uses same argument names as stringr,
  and gains a negate argument (#444).

• semi_join() and anti_join() now correctly support the sql_on argument
  (#443, @krlmlr).

• dbplyr now uses RPostgres (instead of RPostgreSQL) and RMariaDB (instead of
  RMySQL) for its internal tests and data functions (#427).

• The Date and POSIXt methods for escape() now use exported
  sql_escape_date() and sql_escape_datetime() generics to allow backend
  specific formatting of date and datetime literals. These are used to
  provide methods for Athena and Presto backends (@OssiLehtinen, #384, #391).

• first(), last(), nth(), lead() and lag() now respect the
  window_frame() (@krlmlr, #366).

• SQL server: new translations for str_flatten() (@PauloJhonny, #405).

• SQL server: temporary datasets are now session-local, not global (#401).

• Postgres: correct str_detect(), str_replace() and str_replace_all()
  translation (@shosaco, #362).

• Fix bug when partially evaluating unquoting quosure containing a single
  symbol (#317)

• Fixes for rlang and dpylr compatibility.

Minor improvements to SQL generation

• x %in% y strips names of y (#269).

• Enhancements for scoped verbs (mutate_all(), summarise_if(),
  filter_at() etc) (#296, #306).

• MS SQL use TOP 100 PERCENT as stop-gap to allow subqueries with
  ORDER BY (#277).

• Window functions now translated correctly for Hive (#293, @cderv).

Breaking changes

• Error: `con` must not be NULL: If you see this error, it probably means
  that you have probably forgotten to pass con down to a dbplyr function.
  Previously, dbplyr defaulted to using simulate_dbi() which introduced
  subtle escaping bugs. (It's also possible I have forgotten to pass it
  somewhere that the dbplyr tests don't pick up, so if you can't figure it
  out, please let me know).

• Subsetting ([[, $, and [) functions are no longer evaluated locally.
  This makes the translation more consistent and enables useful new idioms
  for modern databases (#200).

New features

• MySQL/MariaDB (https://mariadb.com/kb/en/library/window-functions/)
  and SQLite (https://www.sqlite.org/windowfunctions.html) translations gain
  support for window functions, available in Maria DB 10.2, MySQL 8.0, and
  SQLite 3.25 (#191).

• Overall, dplyr generates many fewer subqueries:

  • Joins and semi-joins no longer add an unneeded subquery (#236). This is
    faciliated by the new bare_identifier_ok argument to sql_render();
    the previous argument was called root and confused me.

  • Many sequences of select(), rename(), mutate(), and transmute() can
    be collapsed into a single query, instead of always generating a subquery
    (#213).

• New vignette("sql") describes some advantages of dbplyr over SQL (#205) and
  gives some advice about writing how to write literal SQL inside of dplyr,
  when you you need to (#196).

• New vignette("reprex") gives some hints on creating reprexes that work
  anywhere (#117). This is supposrted by a new tbl_memdb() that
  matches the existing tbl_lazy().

• All ..._join() functions gain an sql_on argument that allows specifying
  arbitrary join predicates in SQL code (#146, @krlmlr).

SQL translations

• New translations for some lubridate functions: today(), now(),
  year(), month(), day(), hour(), minute(),
  second(), quarter(), ``yday()(@colearendt, @derekmorr). Also added new translation foras.POSIXct()`.

• New translations for stringr functions: str_c(), str_sub(),
  str_length(), str_to_upper(), str_to_lower(), and str_to_title()
  (@colearendt). Non-translated stringr functions throw a clear error.

• New translations for bitwise operations: bitwNot(), bitwAnd(), bitwOr(),
  bitwXor(), bitwShiftL(), and bitwShiftR(). Unlike the base R functions,
  the translations do not coerce arguments to integers (@davidchall, #235).

• New translation for x[y] to CASE WHEN y THEN x END. This enables
  sum(a[b == 0]) to work as you expect from R (#202). y needs to be
  a logical expression; if not you will likely get a type error from your
  database.

• New translations for x$y and x[["y"]] to x.y, enabling you to index
  into nested fields in databases that provide them (#158).

• The .data and .env pronouns of tidy evaluation are correctly translated
  (#132).

• New translation for median() and quantile(). Works for all ANSI compliant
  databases (SQL Server, Postgres, MariaDB, Teradata) and has custom
  translations for Hive. Thanks to @edavidaja for researching the SQL variants!
  (#169)

• na_if() is correct translated to NULLIF() (rather than NULL_IF) (#211).

• n_distinct() translation throws an error when given more than one argument.
  (#101, #133).

• New default translations for paste(), paste0(), and the hyperbolic
  functions (these previously were only available for ODBC databases).

• Corrected translations of pmin() and pmax() to LEAST() and GREATEST()
  for ANSI compliant databases (#118), to MIN() and MAX() for SQLite, and
  to an error for SQL server.

• New translation for switch() to the simple form of CASE WHEN (#192).

SQL simulation

SQL simulation makes it possible to see what dbplyr will translate SQL to, without having an active database connection, and is used for testing and generating reprexes.

• SQL simulation has been overhauled. It now works reliably, is better
  documented, and always uses ANSI escaping (i.e. ` for field
  names and ' for strings).

• tbl_lazy() now actually puts a dbplyr::src in the $src field. This
  shouldn't affect any downstream code unless you were previously working
  around this weird difference between tbl_lazy and tbl_sql classes.
  It also includes the src class in its class, and when printed,
  shows the generated SQL (#111).

Database specific improvements

• MySQL/MariaDB

  • Translations also applied to connections via the odbc package
    (@colearendt, #238)

  • Basic support for regular expressions via str_detect() and
    str_replace_all() (@colearendt, #168).

  • Improved translation for as.logical(x) to IF(x, TRUE, FALSE).

• Oracle

  • New custom translation for paste() and paste0() (@cderv, #221)

• Postgres

  • Basic support for regular expressions via str_detect() and
    str_replace_all() (@colearendt, #168).

• SQLite

  • explain() translation now generates EXPLAIN QUERY PLAN which
    generates a higher-level, more human friendly explanation.

• SQL server

  • Improved translation for as.logical(x) to CAST(x as BIT) (#250).

  • Translates paste(), paste0(), and str_c() to +.

  • copy_to() method applies temporary table name transformation
    earlier so that you can now overwrite temporary tables (#258).

  • db_write_table() method uses correct argument name for
    passing along field types (#251).

Minor improvements and bug fixes

• Aggregation functions only warn once per session about the use of
  na.rm = TRUE (#216).

• table names generated by random_table_name() have the prefix
  "dbplyr_", which makes it easier to find them programmatically
  (@mattle24, #111)

• Functions that are only available in a windowed (mutate()) query now
  throw an error when called in a aggregate (summarise()) query (#129)

• arrange() understands the .by_group argument, making it possible
  sort by groups if desired. The default is FALSE (#115)

• distinct() now handles computed variables like distinct(df, y = x + y)
  (#154).

• escape(), sql_expr() and build_sql() no longer accept con = NULL as
  a shortcut for con = simulate_dbi(). This made it too easy to forget to
  pass con along, introducing extremely subtle escaping bugs. win_over()
  gains a con argument for the same reason.

• New escape_ansi() always uses ANSI SQL 92 standard escaping (for use
  in examples and documentation).

• mutate(df, x = NULL) drops x from the output, just like when working with
  local data frames (#194).

• partial_eval() processes inlined functions (including rlang lambda
  functions). This makes dbplyr work with more forms of scoped verbs like
  df %>% summarise_all(~ mean(.)), df %>% summarise_all(list(mean)) (#134).

• sql_aggregate() now takes an optional argument f_r for passing to
  check_na_rm(). This allows the warning to show the R function name rather
  than the SQL function name (@sverchkov, #153).

• sql_infix() gains a pad argument for the rare operator that doesn't
  need to be surrounded by spaces.

• sql_prefix() no longer turns SQL functions into uppercase, allowing for
  correct translation of case-sensitive SQL functions (#181, @mtoto).

• summarise() gives a clear error message if you refer to a variable
  created in that same summarise() (#114).

• New sql_call2() which is to rlang::call2() as sql_expr() is to
  rlang::expr().

• show_query() and explain() use cat() rather than message.

• union(), union_all(), setdiff() and intersect() do a better job
  of matching columns across backends (#183).

• Now support for dplyr 0.8.0 (#190) and R 3.1.0

API changes

• Calls of the form dplyr::foo() are now evaluated in the database,
  rather than locally (#197).

• vars argument to tbl_sql() has been formally deprecated; it hasn't
  actually done anything for a while (#3254).

• src and tbl objects now include a class generated from the class of
  the underlying connection object. This makes it possible for dplyr backends
  to implement different behaviour at the dplyr level, when needed. (#2293)

SQL translation

• x %in% y is now translated to FALSE if y is empty (@mgirlich, #160).

• New as.integer64(x) translation to CAST(x AS BIGINT) (#3305)

• case_when now translates with a ELSE clause if a formula of the form
  TRUE~<RHS> is provided . (@cderv, #112)

• cummean() now generates AVG() not MEAN() (#157)

• str_detect() now uses correct parameter order (#3397)

• MS SQL

  • Cumulative summary functions now work (#157)
  • ifelse() uses CASE WHEN instead of IIF; this allows more complex
    operations, such as %in%, to work properly (#93)

• Oracle

  • Custom db_drop_table() now only drops tables if they exist (#3306)
  • Custom setdiff() translation (#3493)
  • Custom db_explain() translation (#3471)

• SQLite

  • Correct translation for as.numeric()/as.double() (@chris-park, #171).

• Redshift

  • substr() translation improved (#3339)

Minor improvements and bug fixes

• copy_to() will only remove existing table when overwrite = TRUE and the
  table already exists, eliminating a confusing "NOTICE" from PostgreSQL
  (#3197).

• partial_eval() handles unevaluated formulas (#184).

• pull.tbl_sql() now extracts correctly from grouped tables (#3562).

• sql_render.op() now correctly forwards the con argument (@kevinykuo, #73).

• Forward compatibility fixes for rlang 0.2.0

New top-level translations

• New translations for

  • MS Access (#2946) (@DavisVaughan)
  • Oracle, via odbc or ROracle (#2928, #2732, @edgararuiz)
  • Teradata.
  • Redshift.

• dbplyr now supplies appropriate translations for the RMariaDB and
  RPostgres packages (#3154). We generally recommend using these packages
  in favour of the older RMySQL and RPostgreSQL packages as they are
  fully DBI compliant and tested with DBItest.

New features

• copy_to() can now "copy" tbl_sql in the same src, providing another
  way to cache a query into a temporary table (#3064). You can also
  copy_to tbl_sqls from another source, and copy_to() will automatically
  collect then copy.

• Initial support for stringr functions: str_length(), str_to_upper(),
  str_to_lower(), str_replace_all(), str_detect(), str_trim().
  Regular expression support varies from database to database, but most
  simple regular expressions should be ok.

Tools for developers

• db_compute() gains an analyze argument to match db_copy_to().

• New remote_name(), remote_con(), remote_src(), remote_query() and
  remote_query_plan() provide a standard API for get metadata about a
  remote tbl (#3130, #2923, #2824).

• New sql_expr() is a more convenient building block for low-level SQL
  translation (#3169).

• New sql_aggregate() and win_aggregate() for generating SQL and windowed
  SQL functions for aggregates. These take one argument, x, and warn if
  na.rm is not TRUE (#3155). win_recycled() is equivalent to
  win_aggregate() and has been soft-deprecated.

• db_write_table now needs to return the table name

Minor improvements and bug fixes

• Multiple head() calls in a row now collapse to a single call. This avoids
  a printing problem with MS SQL (#3084).

• escape() now works with integer64 values from the bit64 package (#3230)

• if, ifelse(), and if_else() now correctly scope the false condition
  so that it only applies to non-NULL conditions (#3157)

• ident() and ident_q() handle 0-length inputs better, and should
  be easier to use with S3 (#3212)

• in_schema() should now work in more places, particularly in copy_to()
  (#3013, @baileych)

• SQL generation for joins no longer gets stuck in a endless loop if you
  request an empty suffix (#3220).

• mutate() has better logic for splitting a single mutate into multiple
  subqueries (#3095).

• Improved paste() and paste0() support in MySQL, PostgreSQL (#3168),
  and RSQLite (#3176). MySQL and PostgreSQL gain support for str_flatten()
  which behaves like paste(x, collapse = "-") (but for technical reasons
  can't be implemented as a straightforward translation of paste()).

• same_src.tbl_sql() now performs correct comparison instead of always
  returning TRUE. This means that copy = TRUE once again allows you to
  perform cross-database joins (#3002).

• select() queries no longer alias column names unnecessarily
  (#2968, @DavisVaughan).

• select() and rename() are now powered by tidyselect,
  fixing a few renaming bugs (#3132, #2943, #2860).

• summarise() once again performs partial evaluation before database
  submission (#3148).

• test_src() makes it easier to access a single test source.

Database specific improvements

• MS SQL

  • Better support for temporary tables (@Hong-Revo)

  • Different translations for filter/mutate contexts for: NULL evaluation
    (is.na(), is.null()), logical operators (!, &, &&, |, ||),
    and comparison operators (==, !=, <, >, >=, <=)

• MySQL: copy_to() (via db_write_table()) correctly translates logical
  variables to integers (#3151).

• odbc: improved n() translation in windowed context.

• SQLite: improved na_if translation (@cwarden)

• PostgreSQL: translation for grepl() added (@zozlak)