Fix(postgres): allow FOR clause without FROM in SUBSTRING closes #3377

tobymao · Apr 30, 2024 · 3e8de71 · 3e8de71
1 parent 60b5c3b
commit 3e8de71
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/sqlglot/parser.py b/sqlglot/parser.py
@@ -5315,8 +5315,10 @@ def _parse_substring(self) -> exp.Substring:
 
         if self._match(TokenType.FROM):
             args.append(self._parse_bitwise())
-            if self._match(TokenType.FOR):
-                args.append(self._parse_bitwise())
+        if self._match(TokenType.FOR):
+            if len(args) == 1:
+                args.append(exp.Literal.number(1))
+            args.append(self._parse_bitwise())
 
         return self.validate_expression(exp.Substring.from_arg_list(args), args)
 

diff --git a/tests/dialects/test_postgres.py b/tests/dialects/test_postgres.py
@@ -312,7 +312,14 @@ def test_postgres(self):
             "MERGE INTO x USING (SELECT id) AS y ON a = b WHEN MATCHED THEN UPDATE SET x.a = y.b WHEN NOT MATCHED THEN INSERT (a, b) VALUES (y.a, y.b)",
             "MERGE INTO x USING (SELECT id) AS y ON a = b WHEN MATCHED THEN UPDATE SET a = y.b WHEN NOT MATCHED THEN INSERT (a, b) VALUES (y.a, y.b)",
         )
-        self.validate_identity("SELECT * FROM t1*", "SELECT * FROM t1")
+        self.validate_identity(
+            "SELECT * FROM t1*",
+            "SELECT * FROM t1",
+        )
+        self.validate_identity(
+            "SELECT SUBSTRING('afafa' for 1)",
+            "SELECT SUBSTRING('afafa' FROM 1 FOR 1)",
+        )
 
         self.validate_all(
             "CREATE TABLE t (c INT)",