[SPARK-7886] Added unit test for HAVING aggregate pushdown.

This is a followup to apache#6712.

Author: Reynold Xin <[email protected]>

Closes apache#6739 from rxin/6712-followup and squashes the following commits:

fd9acfb [Reynold Xin] [SPARK-7886] Added unit test for HAVING aggregate pushdown.

Author: rxin

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -38,6 +38,13 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll with SQLTestUtils {
   import sqlContext.implicits._
   import sqlContext.sql
 
+  test("having clause") {
+    Seq(("one", 1), ("two", 2), ("three", 3), ("one", 5)).toDF("k", "v").registerTempTable("hav")
+    checkAnswer(
+      sql("SELECT k, sum(v) FROM hav GROUP BY k HAVING sum(v) > 2"),
+      Row("one", 6) :: Row("three", 3) :: Nil)
+  }
+
   test("SPARK-6743: no columns from cache") {
     Seq(
       (83, 0, 38),

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveQl.scala

@@ -1307,7 +1307,6 @@ https://cwiki.apache.org/confluence/display/Hive/Enhanced+Aggregation%2C+Cube%2C
     HiveParser.DecimalLiteral)
 
   /* Case insensitive matches */
-  val COALESCE = "(?i)COALESCE".r
   val COUNT = "(?i)COUNT".r
   val SUM = "(?i)SUM".r
   val AND = "(?i)AND".r