MySQL: Add support for SELECT modifiers#2172
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iffyio merged 2 commits intoapache:mainfrom Feb 5, 2026
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src/parser/mod.rs
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| let mut distinct: Option<Distinct> = None; | ||
| let mut has_all = false; |
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Can we instead introduce a proper enum to represent the three states? the current impl I think is harder to follow which combinations are valid and if/when the specified option is ignored in the output.
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Yeah, sure. Is this what you have in mind?
enum Distinct {
All,
Distinct,
On(Vec<Expr),
}I'll go ahead and implement that, but let me know if you had something else in mind that I'll be happy to update it..
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lmk what you think. I also reworked it a bit so that DISTINCTROW aliasing only happens here and not in the main parse_all_or_distinct which I believe addresses your other comment.
Previously, `SELECT ALL` was parsed but the ALL keyword was discarded, with `one_statement_parses_to` tests verifying it normalized away. Now the parser returns `Distinct::All` so the AST represents the original SQL. Also improves error messages for conflicting ALL/DISTINCT to indicate which keyword came first.
Adds support for MySQL-specific `SELECT` modifiers that appear after the
`SELECT` keyword. Grammar from the [docs]:
```sql
SELECT
[ALL | DISTINCT | DISTINCTROW ]
[HIGH_PRIORITY]
[STRAIGHT_JOIN]
[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
[SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
select_expr [, select_expr] ...
```
Manual testing shows that these options can appear in any order relative
to each other, so for the sake of fidelity, we parse this separately
from how we parse distinct and other options for other dialects, in a
new `Parser::parse_select_modifiers` method.
`DISTINCTROW` is a legacy (but not deprecated) synonym for `DISTINCT`,
so it just gets canonicalized as `DISTINCT`.
[docs]: https://dev.mysql.com/doc/refman/8.4/en/select.html
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Adds support for MySQL-specific
SELECTmodifiers that appear after theSELECTkeyword. Grammar from the docs:Manual testing shows that these options can appear in any order relative to each other, so for the sake of fidelity, we parse this separately from how we parse distinct and other options for other dialects, in a new
Parser::parse_select_modifiersmethod.DISTINCTROWis a legacy (but not deprecated) synonym forDISTINCT, so it just gets canonicalized asDISTINCT.