[SPARK-5029][SQL] Enable from follow multiple brackets

Enable from follow multiple brackets:
```
select key from ((select * from testData limit 1) union all (select * from testData limit 1)) x limit 1
```

Author: scwf <wangfei1@huawei.com>

Closes #3853 from scwf/from and squashes the following commits:

14f110a [scwf] enable from follow multiple brackets

2 files changed, 18 insertions, 1 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala
index fc7b874559..5d974df98b 100755
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala
@@ -125,7 +125,7 @@ class SqlParser extends AbstractSparkSQLParser {
   }
 
   protected lazy val start: Parser[LogicalPlan] =
-    ( select *
+    ( (select | ("(" ~> select <~ ")")) *
       ( UNION ~ ALL        ^^^ { (q1: LogicalPlan, q2: LogicalPlan) => Union(q1, q2) }
       | INTERSECT          ^^^ { (q1: LogicalPlan, q2: LogicalPlan) => Intersect(q1, q2) }
       | EXCEPT             ^^^ { (q1: LogicalPlan, q2: LogicalPlan) => Except(q1, q2)}
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
index add4e218a2..d9de5686dc 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala
@@ -272,6 +272,23 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll {
       mapData.collect().take(1).toSeq)
   }
 
+  test("from follow multiple brackets") {
+    checkAnswer(sql(
+      "select key from ((select * from testData limit 1) union all (select * from testData limit 1)) x limit 1"),
+      1
+    )
+
+    checkAnswer(sql(
+      "select key from (select * from testData) x limit 1"),
+      1
+    )
+
+    checkAnswer(sql(
+      "select key from (select * from testData limit 1 union all select * from testData limit 1) x limit 1"),
+      1
+    )
+  }
+
   test("average") {
     checkAnswer(
       sql("SELECT AVG(a) FROM testData2"),