Update test.

tests/queries/0_stateless/01881_union_header_mismatch_bug.reference

@@ -1 +1,11 @@
 table	10	101
+a	0
+a	1
+a	2
+a	3
+a	4
+b	0
+b	1
+b	2
+b	3
+b	4

tests/queries/0_stateless/01881_union_header_mismatch_bug.sql

@@ -1 +1,30 @@
-select *　from (　select 'table' as table, toInt64(10) as rows, toInt64(101) as elements　union all　select 'another table' as table, toInt64(0) as rows, toInt64(0) as elements　)　where rows - elements <> 0
+select *　from (　select 'table' as table, toInt64(10) as rows, toInt64(101) as elements　union all　select 'another table' as table, toInt64(0) as rows, toInt64(0) as elements　)　where rows - elements <> 0;
+
+SELECT
+    label,
+    number
+FROM
+(
+    SELECT
+        'a' AS label,
+        number
+    FROM
+    (
+        SELECT number
+        FROM numbers(10)
+    )
+    UNION ALL
+    SELECT
+        'b' AS label,
+        number
+    FROM
+    (
+        SELECT number
+        FROM numbers(10)
+    )
+)
+WHERE number IN
+(
+    SELECT number
+    FROM numbers(5)
+) order by label, number;