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Add STRING_AGG as alias of groupConcat#105125
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PostgreSQL/SQL-standard `STRING_AGG(expr, sep)` matches ClickHouse's existing `groupConcat(expr, sep)` exactly when the separator is passed as a regular argument. Expose `STRING_AGG` as a case-insensitive alias so PostgreSQL-dialect queries (e.g., the SQLStorm corpus) do not need rewriting. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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alexey-milovidov
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May 16, 2026
Recent compatibility PRs added case-insensitive aliases and parser sugar that make several of the SQLStorm rewrites unnecessary: - `STDDEV` -> `stddevPop` (#105120) - `array_to_string` -> `arrayStringConcat` (#105121) - `REGEXP_SUBSTR` -> `regexpExtract` (#105122) - `CARDINALITY` -> `length` (#105123) - `unnest()` function -> `arrayJoin()` (#105124) - `STRING_AGG` -> `groupConcat` (#105125) - `date_part(unit,e)` -> `EXTRACT(unit FROM e)` (#105127) - `expr OP ANY/ALL(array_literal)` (#105129) `ARRAY_AGG`, `TRANSLATE`, and `EXTRACT(EPOCH|DOW|... FROM ...)` were already supported by ClickHouse before these PRs. Removed the corresponding rewrite calls and helper functions (`rewrite_string_agg`, `rewrite_array_agg`, `rewrite_date_part`, `rewrite_stddev`, `rewrite_extract_epoch`, the EXTRACT(DOW) inline rewrite, `rewrite_any_comparison`, and the trailing `unnest(...) -> arrayJoin(...)` substitution). Also dropped the unreferenced no-op helpers (`rewrite_extract_unit`, `rewrite_fetch_offset`, `rewrite_interval`, `rewrite_cast_timestamp`, `rewrite_current_timestamp`, `rewrite_bool_literals`, `rewrite_ilike`, `rewrite_no_supertype`). The PostgreSQL `LATERAL` / `CROSS JOIN UNNEST(...)` table-source forms, `arrayJoin(...)` in JOIN position, PG-specific casts, `AT TIME ZONE`, `STRING_AGGDistinct` (a mangled-name artifact), and the still-unsupported function rewrites (`string_to_array`, `regexp_split_to_array`, `RANDOM`, `TO_TIMESTAMP`, `ARRAY_LENGTH`, `SPLIT_PART`, `age`) are still rewritten. Net change: -329 lines from rewrite_queries.py and -75 lines from the tests (the `TestRewriteAnyComparison` class is removed since the rewrite it covered no longer exists). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The analyzer rewrites the 2-argument call `groupConcat(expr, sep)` into the parameterized form `groupConcat(sep)(expr)` only for names listed in `GroupConcatImpl<false>::getNameAndAliases` (see `QueryTreeBuilder::setSecondArgumentAsParameter`). The previous alias was registered through `registerAlias` only, so `STRING_AGG(expr, sep)` hit the unary check in `createAggregateFunctionGroupConcat` and failed with `NUMBER_OF_ARGUMENTS_DOESNT_MATCH`. Add `string_agg` to `getNameAndAliases` so the rewrite triggers, and register every alias from that list in `registerAggregateFunctionGroupConcat`. Failure: https://s3.amazonaws.com/clickhouse-test-reports/json.html?PR=105125&sha=28eefc28ebcdb622ae3d79b79d96e3563e495faa&name_0=PR&name_1=Fast%20test PR: #105125 Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
m-selmi
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May 18, 2026
The 2-argument form `STRING_AGG(expr, sep)` (and equivalently `groupConcat(expr, sep)`) is rewritten into the parameterized form `STRING_AGG(sep)(expr)` only by the new analyzer (see `QueryTreeBuilder::setSecondArgumentAsParameter`). The old analyzer sees two positional arguments and fails with `NUMBER_OF_ARGUMENTS_DOESNT_MATCH`. The test fails under "Stateless tests (amd_llvm_coverage, old analyzer, s3 storage, DatabaseReplicated, WasmEdge, parallel)": https://s3.amazonaws.com/clickhouse-test-reports/json.html?PR=105125&sha=d5baa1fd637c78da6f35bf52e576d0c77223ea48&name_0=PR&name_1=Stateless%20tests%20%28amd_llvm_coverage%2C%20old%20analyzer%2C%20s3%20storage%2C%20DatabaseReplicated%2C%20WasmEdge%2C%20parallel%29 Pin the 2-argument queries to `enable_analyzer=1`, matching the existing convention in `03156_group_concat.sql`. The 1-argument form remains analyzer-agnostic. PR: #105125 Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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LLVM Coverage ReportChanged lines: 100.00% (7/7) · Uncovered code |
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PostgreSQL/SQL-standard
STRING_AGG(expr, sep)matches ClickHouse's existinggroupConcat(expr, sep)exactly when the separator is passed as a regular argument. Adding a case-insensitive alias spares PostgreSQL-dialect workloads (such as the SQLStorm corpus) a rewrite.Changelog category (leave one):
Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):
Added
STRING_AGGas a case-insensitive alias ofgroupConcatfor PostgreSQL/SQL-standard compatibility.Documentation entry for user-facing changes
Version info
26.5.1.850