MySQL: support for GROUP_CONCAT() (#1256)

src/ast/mod.rs

@@ -4962,6 +4962,10 @@ pub enum FunctionArgumentClause {
     ///
     /// See <https://trino.io/docs/current/functions/aggregate.html>.
     OnOverflow(ListAggOnOverflow),
+    /// The `SEPARATOR` clause to the [`GROUP_CONCAT`] function in MySQL.
+    ///
+    /// [`GROUP_CONCAT`]: https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_group-concat
+    Separator(Value),
 }
 
 impl fmt::Display for FunctionArgumentClause {
@@ -4975,6 +4979,7 @@ impl fmt::Display for FunctionArgumentClause {
             }
             FunctionArgumentClause::Limit(limit) => write!(f, "LIMIT {limit}"),
             FunctionArgumentClause::OnOverflow(on_overflow) => write!(f, "{on_overflow}"),
+            FunctionArgumentClause::Separator(sep) => write!(f, "SEPARATOR {sep}"),
         }
     }
 }

src/keywords.rs

@@ -616,6 +616,7 @@ define_keywords!(
     SELECT,
     SEMI,
     SENSITIVE,
+    SEPARATOR,
     SEQUENCE,
     SEQUENCEFILE,
     SEQUENCES,

src/parser/mod.rs

@@ -9488,6 +9488,12 @@ impl<'a> Parser<'a> {
             clauses.push(FunctionArgumentClause::Limit(self.parse_expr()?));
         }
 
+        if dialect_of!(self is GenericDialect | MySqlDialect)
+            && self.parse_keyword(Keyword::SEPARATOR)
+        {
+            clauses.push(FunctionArgumentClause::Separator(self.parse_value()?));
+        }
+
         if let Some(on_overflow) = self.parse_listagg_on_overflow()? {
             clauses.push(FunctionArgumentClause::OnOverflow(on_overflow));
         }

tests/sqlparser_mysql.rs

@@ -2706,3 +2706,14 @@ fn parse_json_table() {
         }
     );
 }
+
+#[test]
+fn test_group_concat() {
+    // examples taken from mysql docs
+    // https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_group-concat
+    mysql_and_generic().verified_expr("GROUP_CONCAT(DISTINCT test_score)");
+    mysql_and_generic().verified_expr("GROUP_CONCAT(test_score ORDER BY test_score)");
+    mysql_and_generic().verified_expr("GROUP_CONCAT(test_score SEPARATOR ' ')");
+    mysql_and_generic()
+        .verified_expr("GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')");
+}