Fix(clickhouse)!: dont parse right-hand side operands of ARRAY JOIN a…

…s Tables (#4258)

* Fix(clickhouse)!: dont parse right-hand side operands of ARRAY JOIN as Tables

* Refactor, address PR feedback

sqlglot/dialects/clickhouse.py

@@ -603,6 +603,12 @@ def _parse_join(
             if join:
                 join.set("global", join.args.pop("method", None))
 
+                # tbl ARRAY JOIN arr <-- this should be a `Column` reference, not a `Table`
+                # https://clickhouse.com/docs/en/sql-reference/statements/select/array-join
+                if join.kind == "ARRAY":
+                    for table in join.find_all(exp.Table):
+                        table.replace(table.to_column())
+
             return join
 
         def _parse_function(

sqlglot/expressions.py

@@ -3214,10 +3214,18 @@ def parts(self) -> t.List[Expression]:
 
     def to_column(self, copy: bool = True) -> Alias | Column | Dot:
         parts = self.parts
-        col = column(*reversed(parts[0:4]), fields=parts[4:], copy=copy)  # type: ignore
+        last_part = parts[-1]
+
+        if isinstance(last_part, Identifier):
+            col = column(*reversed(parts[0:4]), fields=parts[4:], copy=copy)  # type: ignore
+        else:
+            # This branch will be reached if a function or array is wrapped in a `Table`
+            col = last_part
+
         alias = self.args.get("alias")
         if alias:
             col = alias_(col, alias.this, copy=copy)
+
         return col
 
 

tests/dialects/test_clickhouse.py

@@ -421,14 +421,6 @@ def test_clickhouse(self):
                 " GROUP BY loyalty ORDER BY loyalty ASC"
             },
         )
-        self.validate_identity("SELECT s, arr FROM arrays_test ARRAY JOIN arr")
-        self.validate_identity("SELECT s, arr, a FROM arrays_test LEFT ARRAY JOIN arr AS a")
-        self.validate_identity(
-            "SELECT s, arr_external FROM arrays_test ARRAY JOIN [1, 2, 3] AS arr_external"
-        )
-        self.validate_identity(
-            "SELECT * FROM tbl ARRAY JOIN [1, 2, 3] AS arr_external1, ['a', 'b', 'c'] AS arr_external2, splitByString(',', 'asd,qwerty,zxc') AS arr_external3"
-        )
         self.validate_all(
             "SELECT quantile(0.5)(a)",
             read={"duckdb": "SELECT quantile(a, 0.5)"},
@@ -1104,3 +1096,30 @@ def test_convert(self):
     def test_grant(self):
         self.validate_identity("GRANT SELECT(x, y) ON db.table TO john WITH GRANT OPTION")
         self.validate_identity("GRANT INSERT(x, y) ON db.table TO john")
+
+    def test_array_join(self):
+        expr = self.validate_identity(
+            "SELECT * FROM arrays_test ARRAY JOIN arr1, arrays_test.arr2 AS foo, ['a', 'b', 'c'] AS elem"
+        )
+        joins = expr.args["joins"]
+        self.assertEqual(len(joins), 1)
+
+        join = joins[0]
+        self.assertEqual(join.kind, "ARRAY")
+        self.assertIsInstance(join.this, exp.Column)
+
+        self.assertEqual(len(join.expressions), 2)
+        self.assertIsInstance(join.expressions[0], exp.Alias)
+        self.assertIsInstance(join.expressions[0].this, exp.Column)
+
+        self.assertIsInstance(join.expressions[1], exp.Alias)
+        self.assertIsInstance(join.expressions[1].this, exp.Array)
+
+        self.validate_identity("SELECT s, arr FROM arrays_test ARRAY JOIN arr")
+        self.validate_identity("SELECT s, arr, a FROM arrays_test LEFT ARRAY JOIN arr AS a")
+        self.validate_identity(
+            "SELECT s, arr_external FROM arrays_test ARRAY JOIN [1, 2, 3] AS arr_external"
+        )
+        self.validate_identity(
+            "SELECT * FROM arrays_test ARRAY JOIN [1, 2, 3] AS arr_external1, ['a', 'b', 'c'] AS arr_external2, splitByString(',', 'asd,qwerty,zxc') AS arr_external3"
+        )

tests/fixtures/optimizer/qualify_columns.sql

@@ -196,6 +196,11 @@ SELECT SOME_UDF(t.data).* FROM t AS t;
 SELECT a + 1 AS i, missing_column FROM x;
 SELECT x.a + 1 AS i, missing_column AS missing_column FROM x AS x;
 
+# execute: false
+# dialect: clickhouse
+SELECT s, arr1, arr2 FROM arrays_test LEFT ARRAY JOIN arr1, arrays_test.arr2;
+SELECT arrays_test.s AS s, arrays_test.arr1 AS arr1, arrays_test.arr2 AS arr2 FROM arrays_test AS arrays_test LEFT ARRAY JOIN arrays_test.arr1, arrays_test.arr2;
+
 --------------------------------------
 -- Derived tables
 --------------------------------------