Hive.GROUPING SETS

干货

Aggregate Query with GROUPING SETS	Equivalent Aggregate Query with GROUP BY
SELECT a, b, SUM(c) FROM tab1 GROUP BY a, b GROUPING SETS ( (a,b) )	SELECT a, b, SUM(c) FROM tab1 GROUP BY a, b
SELECT a, b, SUM( c ) FROM tab1 GROUP BY a, b GROUPING SETS ( (a,b), a)	SELECT a, b, SUM( c ) FROM tab1 GROUP BY a, b UNION SELECT a, null, SUM( c ) FROM tab1 GROUP BY a
SELECT a,b, SUM( c ) FROM tab1 GROUP BY a, b GROUPING SETS (a,b)	SELECT a, null, SUM( c ) FROM tab1 GROUP BY a UNION SELECT null, b, SUM( c ) FROM tab1 GROUP BY b
SELECT a, b, SUM( c ) FROM tab1 GROUP BY a, b GROUPING SETS ( (a, b), a, b, ( ) )	SELECT a, b, SUM( c ) FROM tab1 GROUP BY a, b UNION SELECT a, null, SUM( c ) FROM tab1 GROUP BY a, null UNION SELECT null, b, SUM( c ) FROM tab1 GROUP BY null, b UNION SELECT null, null, SUM( c ) FROM tab1

其中的null可以用nvl转化下。