sql问题--case-when

一、 有表以下，请使用查询语句得出相应结果

id	job	createdate
1	开发	2018-06-19
2	运维	2018-06-20
3	开发	2018-06-19
4	开发	2018-06-20

得出以下结果

createdate	开发	运维
2018-06-19	2	0
2018-06-20	1	1

 

答案：

         SELECT

         aa.createdate,

         SUM(

                  CASE

                  WHEN aa.job = '开发' THEN

                          1

                  ELSE

                          0

                  END

         ) '开发',

         SUM(

                  CASE

                  WHEN aa.job = '运维' THEN

                          1

                  ELSE

                          0

                  END

         ) '运维'

FROM

                  testtable aa

GROUP BY

                  aa.createdate;