[SPARK-12720][SQL] SQL Generation Support for Cube, Rollup, and Grouping Sets

#### What changes were proposed in this pull request?

This PR is for supporting SQL generation for cube, rollup and grouping sets.

For example, a query using rollup:
```SQL
SELECT count(*) as cnt, key % 5, grouping_id() FROM t1 GROUP BY key % 5 WITH ROLLUP
```
Original logical plan:
```
  Aggregate [(key#17L % cast(5 as bigint))#47L,grouping__id#46],
            [(count(1),mode=Complete,isDistinct=false) AS cnt#43L,
             (key#17L % cast(5 as bigint))#47L AS _c1#45L,
             grouping__id#46 AS _c2#44]
  +- Expand [List(key#17L, value#18, (key#17L % cast(5 as bigint))#47L, 0),
             List(key#17L, value#18, null, 1)],
            [key#17L,value#18,(key#17L % cast(5 as bigint))#47L,grouping__id#46]
     +- Project [key#17L,
                 value#18,
                 (key#17L % cast(5 as bigint)) AS (key#17L % cast(5 as bigint))#47L]
        +- Subquery t1
           +- Relation[key#17L,value#18] ParquetRelation
```
Converted SQL:
```SQL
  SELECT count( 1) AS `cnt`,
         (`t1`.`key` % CAST(5 AS BIGINT)),
         grouping_id() AS `_c2`
  FROM `default`.`t1`
  GROUP BY (`t1`.`key` % CAST(5 AS BIGINT))
  GROUPING SETS (((`t1`.`key` % CAST(5 AS BIGINT))), ())
```

#### How was the this patch tested?

Added eight test cases in `LogicalPlanToSQLSuite`.

Author: gatorsmile <gatorsmile@gmail.com>
Author: xiaoli <lixiao1983@gmail.com>
Author: Xiao Li <xiaoli@Xiaos-MacBook-Pro.local>

Closes #11283 from gatorsmile/groupingSetsToSQL.

1 files changed, 7 insertions, 7 deletions

diff --git a/python/pyspark/sql/functions.py b/python/pyspark/sql/functions.py
index 92e724fef4..88924e2981 100644
--- a/python/pyspark/sql/functions.py
+++ b/python/pyspark/sql/functions.py
@@ -348,13 +348,13 @@ def grouping_id(*cols):
     grouping columns).
 
     >>> df.cube("name").agg(grouping_id(), sum("age")).orderBy("name").show()
-    +-----+------------+--------+
-    | name|groupingid()|sum(age)|
-    +-----+------------+--------+
-    | null|           1|       7|
-    |Alice|           0|       2|
-    |  Bob|           0|       5|
-    +-----+------------+--------+
+    +-----+-------------+--------+
+    | name|grouping_id()|sum(age)|
+    +-----+-------------+--------+
+    | null|            1|       7|
+    |Alice|            0|       2|
+    |  Bob|            0|       5|
+    +-----+-------------+--------+
     """
     sc = SparkContext._active_spark_context
     jc = sc._jvm.functions.grouping_id(_to_seq(sc, cols, _to_java_column))