Fix(bigquery): STRING_AGG parsing bug (#1846)

* Fix(bigquery): STRING_AGG parsing bug * Refactor
tobymao · Jun 28, 2023 · abdf34b · abdf34b
1 parent 7cb01a0
commit abdf34b
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Showing 2 changed files with 15 additions and 8 deletions.
diff --git a/sqlglot/parser.py b/sqlglot/parser.py
@@ -3732,20 +3732,23 @@ def _parse_concat(self) -> t.Optional[exp.Expression]:
         )
 
     def _parse_string_agg(self) -> exp.Expression:
-        expression: t.Optional[exp.Expression]
-
         if self._match(TokenType.DISTINCT):
-            args = self._parse_csv(self._parse_conjunction)
-            expression = self.expression(exp.Distinct, expressions=[seq_get(args, 0)])
+            args: t.List[t.Optional[exp.Expression]] = [
+                self.expression(exp.Distinct, expressions=[self._parse_conjunction()])
+            ]
+            if self._match(TokenType.COMMA):
+                args.extend(self._parse_csv(self._parse_conjunction))
         else:
             args = self._parse_csv(self._parse_conjunction)
-            expression = seq_get(args, 0)
 
         index = self._index
         if not self._match(TokenType.R_PAREN):
             # postgres: STRING_AGG([DISTINCT] expression, separator [ORDER BY expression1 {ASC | DESC} [, ...]])
-            order = self._parse_order(this=expression)
-            return self.expression(exp.GroupConcat, this=order, separator=seq_get(args, 1))
+            return self.expression(
+                exp.GroupConcat,
+                this=seq_get(args, 0),
+                separator=self._parse_order(this=seq_get(args, 1)),
+            )
 
         # Checks if we can parse an order clause: WITHIN GROUP (ORDER BY <order_by_expression_list> [ASC | DESC]).
         # This is done "manually", instead of letting _parse_window parse it into an exp.WithinGroup node, so that
@@ -3755,7 +3758,7 @@ def _parse_string_agg(self) -> exp.Expression:
             return self.validate_expression(exp.GroupConcat.from_arg_list(args), args)
 
         self._match_l_paren()  # The corresponding match_r_paren will be called in parse_function (caller)
-        order = self._parse_order(this=expression)
+        order = self._parse_order(this=seq_get(args, 0))
         return self.expression(exp.GroupConcat, this=order, separator=seq_get(args, 1))
 
     def _parse_convert(self, strict: bool) -> t.Optional[exp.Expression]:

diff --git a/tests/dialects/test_bigquery.py b/tests/dialects/test_bigquery.py
@@ -27,6 +27,10 @@ def test_bigquery(self):
         with self.assertRaises(ParseError):
             transpile("SELECT * FROM UNNEST(x) AS x(y)", read="bigquery")
 
+        self.validate_identity("STRING_AGG(a)")
+        self.validate_identity("STRING_AGG(a, ' & ')")
+        self.validate_identity("STRING_AGG(DISTINCT a, ' & ')")
+        self.validate_identity("STRING_AGG(a, ' & ' ORDER BY LENGTH(a))")
         self.validate_identity("DATE(2016, 12, 25)")
         self.validate_identity("DATE(CAST('2016-12-25 23:59:59' AS DATETIME))")
         self.validate_identity("SELECT foo IN UNNEST(bar) AS bla")