fix: Do not always consume BUCKET / TRUNCATE as partitioning keywords

sqlglot/parser.py

@@ -1136,7 +1136,14 @@ class Parser(metaclass=_Parser):
         "TRUNCATE": lambda self: self._parse_partitioned_by_bucket_or_truncate(),
     }
 
-    def _parse_partitioned_by_bucket_or_truncate(self) -> exp.Expression:
+    def _parse_partitioned_by_bucket_or_truncate(self) -> t.Optional[exp.Expression]:
+        if not self._match(TokenType.L_PAREN, advance=False):
+            # Partitioning by bucket or truncate follows the syntax:
+            # PARTITION BY (BUCKET(..) | TRUNCATE(..))
+            # If we don't have parenthesis after each keyword, we should instead parse this as an identifier
+            self._retreat(self._index - 1)
+            return None
+
         klass = (
             exp.PartitionedByBucket
             if self._prev.text.upper() == "BUCKET"

tests/fixtures/identity.sql

@@ -552,6 +552,8 @@ CREATE TABLE a.b AS SELECT a FROM a.c
 CREATE TABLE IF NOT EXISTS x AS SELECT a FROM d
 CREATE TABLE z (a INT, b VARCHAR, c VARCHAR(100), d DECIMAL(5, 3))
 CREATE TABLE z (end INT)
+CREATE TABLE z (bucket INT)
+CREATE TABLE z (truncate INT)
 CREATE TABLE z (a ARRAY<TEXT>, b MAP<TEXT, DOUBLE>, c DECIMAL(5, 3))
 CREATE TABLE z (a INT, b VARCHAR COMMENT 'z', c VARCHAR(100) COMMENT 'z', d DECIMAL(5, 3))
 CREATE TABLE z (a INT(11) DEFAULT UUID())