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Add support for SHOW CHARSET #1974

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Merged
merged 3 commits into from
Jul 29, 2025
Merged

Add support for SHOW CHARSET #1974

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4a53313
SGA-11783 Added support for SHOW CHARSET
etgarperets Jul 24, 2025
9352477
SGA-11783 Address review feedback for SHOW CHARSET
etgarperets Jul 27, 2025
4a73878
Update src/ast/mod.rs
etgarperets Jul 29, 2025
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29 changes: 29 additions & 0 deletions src/ast/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3704,6 +3704,20 @@ pub enum Statement {
history: bool,
show_options: ShowStatementOptions,
},
// ```sql
// SHOW {CHARACTER SET | CHARSET} [like_or_where]
// ```
// where:
// like_or_where: {
// LIKE 'pattern'
// | WHERE expr
// }
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Suggested change
// SHOW {CHARACTER SET | CHARSET} [like_or_where]
// ```
// where:
// like_or_where: {
// LIKE 'pattern'
// | WHERE expr
// }
// SHOW {CHARACTER SET | CHARSET}
// ```

Thinking a brief example would be enough. For detailed syntax readers can follow the documentation

// MySQL specific statement
// <https://dev.mysql.com/doc/refman/8.4/en/show.html#:~:text=SHOW%20%7BCHARACTER%20SET%20%7C%20CHARSET%7D%20%5Blike_or_where%5D>
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Suggested change
// MySQL specific statement
// <https://dev.mysql.com/doc/refman/8.4/en/show.html#:~:text=SHOW%20%7BCHARACTER%20SET%20%7C%20CHARSET%7D%20%5Blike_or_where%5D>
//
[MySQL]: https://dev.mysql.com/doc/refman/8.4/en/show.html#:~:text=SHOW%20%7BCHARACTER%20SET%20%7C%20CHARSET%7D%20%5Blike_or_where%5D

Or something similar, essentially dropping the mention of it being mysql specific, since that can change in the future or other existing dialects might also support it in some form

ShowCharset {
is_shorthand: bool,
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Could we add a description what this flag does?

filter: Option<ShowStatementFilter>,
},
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Can we switch to using a named struct syntax for this statement? See ref we're trying to move away from the anonymous struct syntax ideally.

We could have something like?

struct ShowCharSet { ... }
Statement::ShowCharSet(ShowCharSet{...})

/// ```sql
/// SHOW OBJECTS LIKE 'line%' IN mydb.public
/// ```
Expand Down Expand Up @@ -5674,6 +5688,21 @@ impl fmt::Display for Statement {
}
Ok(())
}
Statement::ShowCharset {
is_shorthand,
filter,
} => {
write!(f, "SHOW")?;
if *is_shorthand {
write!(f, " CHARSET")?;
} else {
write!(f, " CHARACTER SET")?;
}
if filter.is_some() {
write!(f, " {}", filter.as_ref().unwrap())?;
}
Ok(())
}
Statement::StartTransaction {
modes,
begin: syntax_begin,
Expand Down
1 change: 1 addition & 0 deletions src/ast/spans.rs
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Expand Up @@ -477,6 +477,7 @@ impl Spanned for Statement {
Statement::ShowColumns { .. } => Span::empty(),
Statement::ShowTables { .. } => Span::empty(),
Statement::ShowCollation { .. } => Span::empty(),
Statement::ShowCharset { .. } => Span::empty(),
Statement::Use(u) => u.span(),
Statement::StartTransaction { .. } => Span::empty(),
Statement::Comment { .. } => Span::empty(),
Expand Down
12 changes: 12 additions & 0 deletions src/parser/mod.rs
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Expand Up @@ -12505,13 +12505,25 @@ impl<'a> Parser<'a> {
self.parse_show_databases(terse)
} else if self.parse_keyword(Keyword::SCHEMAS) {
self.parse_show_schemas(terse)
} else if self.parse_keywords(&[Keyword::CHARACTER, Keyword::SET]) {
self.parse_show_charset(false)
} else if self.parse_keyword(Keyword::CHARSET) {
self.parse_show_charset(true)
} else {
Ok(Statement::ShowVariable {
variable: self.parse_identifiers()?,
})
}
}

fn parse_show_charset(&mut self, is_shorthand: bool) -> Result<Statement, ParserError> {
// parse one of keywords
Ok(Statement::ShowCharset {
is_shorthand,
filter: self.parse_show_statement_filter()?,
})
}

fn parse_show_databases(&mut self, terse: bool) -> Result<Statement, ParserError> {
let history = self.parse_keyword(Keyword::HISTORY);
let show_options = self.parse_show_stmt_options()?;
Expand Down
8 changes: 8 additions & 0 deletions tests/sqlparser_mysql.rs
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Expand Up @@ -4143,3 +4143,11 @@ fn parse_json_member_of() {
_ => panic!("Unexpected statement {stmt}"),
}
}

#[test]
fn parse_show_charset() {
let _ = mysql().verified_stmt("SHOW CHARACTER SET");
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Since this adds a new node to the AST, can we assert one of the scenarios that the AST looks as expected? For example

let _ = mysql().verified_stmt("SHOW CHARACTER SET LIKE 'utf8mb4%'");
let _ = mysql().verified_stmt("SHOW CHARSET WHERE charset = 'utf8mb4%'");
let _ = mysql().verified_stmt("SHOW CHARSET LIKE 'utf8mb4%'");
}
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