MySQL统计过去12个月的数据没有则为0

查询每月新增用户数

celsp_users是用户表

createTime 为新增用户时间

SELECT a.count,b.time2 from  
(select count(c.createTime) as count,FROM_UNIXTIME( UNIX_TIMESTAMP(c.createTime),'%m' ) as mon 
from celsp_users c where  FROM_UNIXTIME( UNIX_TIMESTAMP(c.createTime),'%Y' ) = '2015' GROUP BY mon) a 
RIGHT JOIN (SELECT '01' as time2 from  DUAL UNION ALL  
SELECT '02' as time2 from  DUAL UNION ALL 
SELECT '03' as time2 from  DUAL UNION ALL 
SELECT '04' as time2 from  DUAL UNION ALL 
SELECT '05' as time2 from  DUAL UNION ALL 
SELECT '06' as time2 from  DUAL UNION ALL 
SELECT '07' as time2 from  DUAL UNION ALL 
SELECT '08' as time2 from  DUAL UNION ALL 
SELECT '09' as time2 from  DUAL UNION ALL 
SELECT '10' as time2 from  DUAL UNION ALL 
SELECT '11' as time2 from  DUAL UNION ALL 
SELECT '12' as time2 from  DUAL )b on a.mon = b.time2

结果集