[SPARK-1995][SQL] system function upper and lower can be supported

I don't know whether it's time to implement system function about string operation in spark sql now.

Author: egraldlo <egraldlo@gmail.com>

Closes #936 from egraldlo/stringoperator and squashes the following commits:

3c6c60a [egraldlo] Add UPPER, LOWER, MAX and MIN into hive parser
ea76d0a [egraldlo] modify the formatting issues
b49f25e [egraldlo] modify the formatting issues
1f0bbb5 [egraldlo] system function upper and lower supported
13d3267 [egraldlo] system function upper and lower supported

1 files changed, 23 insertions, 0 deletions

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 189dccd525..95860e6683 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
@@ -313,4 +313,27 @@ class SQLQuerySuite extends QueryTest {
         (3, "C"),
         (4, "D")))
   }
+  
+  test("system function upper()") {
+    checkAnswer(
+      sql("SELECT n,UPPER(l) FROM lowerCaseData"),
+      Seq(
+        (1, "A"),
+        (2, "B"),
+        (3, "C"),
+        (4, "D")))
+  }
+    
+  test("system function lower()") {
+    checkAnswer(
+      sql("SELECT N,LOWER(L) FROM upperCaseData"),
+      Seq(
+        (1, "a"),
+        (2, "b"),
+        (3, "c"),
+        (4, "d"),
+        (5, "e"),
+        (6, "f")))
+  }  
+  
 }