fix!: snowflake optional merge insert

tobymao · May 2, 2024 · 3768514 · 3768514
1 parent 33bae9b
commit 3768514
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Showing 4 changed files with 16 additions and 8 deletions.
diff --git a/sqlglot/expressions.py b/sqlglot/expressions.py
@@ -2083,7 +2083,7 @@ class Insert(DDL, DML):
         "hint": False,
         "with": False,
         "is_function": False,
-        "this": True,
+        "this": False,
         "expression": False,
         "conflict": False,
         "returning": False,

diff --git a/sqlglot/generator.py b/sqlglot/generator.py
@@ -3353,9 +3353,10 @@ def when_sql(self, expression: exp.When) -> str:
 
         then_expression = expression.args.get("then")
         if isinstance(then_expression, exp.Insert):
-            then = f"INSERT {self.sql(then_expression, 'this')}"
-            if "expression" in then_expression.args:
-                then += f" VALUES {self.sql(then_expression, 'expression')}"
+            this = self.sql(then_expression, "this")
+            this = f"INSERT {this}" if this else "INSERT"
+            then = self.sql(then_expression, "expression")
+            then = f"{this} VALUES {then}" if then else this
         elif isinstance(then_expression, exp.Update):
             if isinstance(then_expression.args.get("expressions"), exp.Star):
                 then = f"UPDATE {self.sql(then_expression, 'expressions')}"
@@ -3377,10 +3378,11 @@ def merge_sql(self, expression: exp.Merge) -> str:
         this = self.sql(table)
         using = f"USING {self.sql(expression, 'using')}"
         on = f"ON {self.sql(expression, 'on')}"
-        expressions = self.expressions(expression, sep=" ")
+        expressions = self.expressions(expression, sep=" ", indent=False)
+        sep = self.sep()
 
         return self.prepend_ctes(
-            expression, f"MERGE INTO {this}{table_alias} {using} {on} {expressions}"
+            expression, f"MERGE INTO {this}{table_alias}{sep}{using}{sep}{on}{sep}{expressions}"
         )
 
     def tochar_sql(self, expression: exp.ToChar) -> str:

diff --git a/sqlglot/parser.py b/sqlglot/parser.py
@@ -2467,14 +2467,17 @@ def _parse_partition(self) -> t.Optional[exp.Partition]:
             exp.Partition, expressions=self._parse_wrapped_csv(self._parse_conjunction)
         )
 
-    def _parse_value(self) -> exp.Tuple:
+    def _parse_value(self) -> t.Optional[exp.Tuple]:
         if self._match(TokenType.L_PAREN):
             expressions = self._parse_csv(self._parse_expression)
             self._match_r_paren()
             return self.expression(exp.Tuple, expressions=expressions)
 
         # In some dialects we can have VALUES 1, 2 which results in 1 column & 2 rows.
-        return self.expression(exp.Tuple, expressions=[self._parse_expression()])
+        expression = self._parse_expression()
+        if expression:
+            return self.expression(exp.Tuple, expressions=[expression])
+        return None
 
     def _parse_projections(self) -> t.List[exp.Expression]:
         return self._parse_expressions()

diff --git a/tests/dialects/test_snowflake.py b/tests/dialects/test_snowflake.py
@@ -10,6 +10,9 @@ class TestSnowflake(Validator):
     dialect = "snowflake"
 
     def test_snowflake(self):
+        self.validate_identity(
+            "MERGE INTO my_db AS ids USING (SELECT new_id FROM my_model WHERE NOT col IS NULL) AS new_ids ON ids.type = new_ids.type AND ids.source = new_ids.source WHEN NOT MATCHED THEN INSERT VALUES (new_ids.new_id)"
+        )
         self.validate_identity("ALTER TABLE table1 CLUSTER BY (name DESC)")
         self.validate_identity(
             "INSERT OVERWRITE TABLE t SELECT 1", "INSERT OVERWRITE INTO t SELECT 1"