mysql列转行以及年月分组实例

SELECT count(DISTINCT(a.rect_id)) zcount, a.job_dept,
DATE_FORMAT(submit_date, '%Y-%m') zsubmit_date
FROM
表名 a
WHERE
a.statu = 3
AND a.rstatu = 2
AND a.job_dept IN ('19', '20', '21')
GROUP BY
a.job_dept,
DATE_FORMAT(submit_date, '%Y-%m')

SELECT      
zsubmit_date,      
MAX(CASE WHEN job_dept = '19' THEN zcount ELSE 0 END ) 19zcount,      
MAX(CASE WHEN job_dept = '20' THEN zcount ELSE 0 END ) 20zcount,      
MAX(CASE WHEN job_dept = '21' THEN zcount ELSE 0 END ) 21zcount  
FROM    
(     
SELECT       
count(DISTINCT(a.rect_id)) zcount, a.job_dept,        
DATE_FORMAT(submit_date, '%Y-%m') zsubmit_date     
FROM       
表名 a     
WHERE       
a.statu = 3       
AND a.rstatu = 2       
AND a.job_dept IN ('19', '20', '21')     
GROUP BY     
a.job_dept,     
DATE_FORMAT(submit_date, '%Y-%m')    
) q  GROUP BY    
zsubmit_date