Add subquery using IN on where clause.

sql/hive/src/test/resources/sqlgen/subquery_in.sql

@@ -0,0 +1,6 @@
+-- This file is automatically generated by LogicalPlanToSQLSuite.
+SELECT key
+FROM src
+WHERE key in (SELECT max(key) FROM src)
+--------------------------------------------------------------------------------
+SELECT `gen_attr_0` AS `key` FROM (SELECT `gen_attr_0` FROM (SELECT `key` AS `gen_attr_0`, `value` AS `gen_attr_2` FROM `default`.`src`) AS gen_subquery_0 WHERE (`gen_attr_0` IN (SELECT `gen_attr_3` AS `_c0` FROM (SELECT `gen_attr_1` AS `gen_attr_3` FROM (SELECT max(`gen_attr_4`) AS `gen_attr_1` FROM (SELECT `key` AS `gen_attr_4`, `value` AS `gen_attr_5` FROM `default`.`src`) AS gen_subquery_2) AS gen_subquery_1) AS gen_subquery_3))) AS src

sql/hive/src/test/scala/org/apache/spark/sql/catalyst/LogicalPlanToSQLSuite.scala

@@ -1063,6 +1063,16 @@ class LogicalPlanToSQLSuite extends SQLBuilderTest with SQLTestUtils {
       "subquery_not_exists_having_2")
   }
 
+  test("subquery using IN on where clause") {
+    checkSQL(
+      """
+        |SELECT key
+        |FROM src
+        |WHERE key in (SELECT max(key) FROM src)
+      """.stripMargin,
+      "subquery_in")
+  }
+
   test("subquery using IN on having clause") {
     checkSQL(
       """