[SPARK-12577] [SQL] Better support of parentheses in partition by and order by...

[SPARK-12577] [SQL] Better support of parentheses in partition by and order by clause of window function's over clause

JIRA: https://issues.apache.org/jira/browse/SPARK-12577

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #10620 from viirya/fix-parentheses.

sql/catalyst/src/main/antlr3/org/apache/spark/sql/catalyst/parser/ExpressionParser.g

@@ -223,7 +223,12 @@ precedenceUnaryPrefixExpression
     ;
 
 precedenceUnarySuffixExpression
-    : precedenceUnaryPrefixExpression (a=KW_IS nullCondition)?
+    :
+    (
+    (LPAREN precedenceUnaryPrefixExpression RPAREN) => LPAREN precedenceUnaryPrefixExpression (a=KW_IS nullCondition)? RPAREN
+    |
+    precedenceUnaryPrefixExpression (a=KW_IS nullCondition)?
+    )
     -> {$a != null}? ^(TOK_FUNCTION nullCondition precedenceUnaryPrefixExpression)
     -> precedenceUnaryPrefixExpression
     ;

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/CatalystQlSuite.scala

@@ -20,17 +20,33 @@ package org.apache.spark.sql.catalyst
 import org.apache.spark.sql.catalyst.plans.PlanTest
 
 class CatalystQlSuite extends PlanTest {
+  val parser = new CatalystQl()
 
   test("parse union/except/intersect") {
-    val paresr = new CatalystQl()
-    paresr.createPlan("select * from t1 union all select * from t2")
-    paresr.createPlan("select * from t1 union distinct select * from t2")
-    paresr.createPlan("select * from t1 union select * from t2")
-    paresr.createPlan("select * from t1 except select * from t2")
-    paresr.createPlan("select * from t1 intersect select * from t2")
-    paresr.createPlan("(select * from t1) union all (select * from t2)")
-    paresr.createPlan("(select * from t1) union distinct (select * from t2)")
-    paresr.createPlan("(select * from t1) union (select * from t2)")
-    paresr.createPlan("select * from ((select * from t1) union (select * from t2)) t")
+    parser.createPlan("select * from t1 union all select * from t2")
+    parser.createPlan("select * from t1 union distinct select * from t2")
+    parser.createPlan("select * from t1 union select * from t2")
+    parser.createPlan("select * from t1 except select * from t2")
+    parser.createPlan("select * from t1 intersect select * from t2")
+    parser.createPlan("(select * from t1) union all (select * from t2)")
+    parser.createPlan("(select * from t1) union distinct (select * from t2)")
+    parser.createPlan("(select * from t1) union (select * from t2)")
+    parser.createPlan("select * from ((select * from t1) union (select * from t2)) t")
+  }
+
+  test("window function: better support of parentheses") {
+    parser.createPlan("select sum(product + 1) over (partition by ((1) + (product / 2)) " +
+      "order by 2) from windowData")
+    parser.createPlan("select sum(product + 1) over (partition by (1 + (product / 2)) " +
+      "order by 2) from windowData")
+    parser.createPlan("select sum(product + 1) over (partition by ((product / 2) + 1) " +
+      "order by 2) from windowData")
+
+    parser.createPlan("select sum(product + 1) over (partition by ((product) + (1)) order by 2) " +
+      "from windowData")
+    parser.createPlan("select sum(product + 1) over (partition by ((product) + 1) order by 2) " +
+      "from windowData")
+    parser.createPlan("select sum(product + 1) over (partition by (product + (1)) order by 2) " +
+      "from windowData")
   }
 }