一个投票活动
假设有A B C 三表
【A--用户表】
UID (ID)
GROUP_ID (组别)
CITY_ID (城市)
【B-照片表】
PID (照片ID)
UID (和A表UID关联)
【C-投票表】
UID (和A表UID关联)
PhotoID (和B表PID关联)
投票流程:
当用户投票成功后,往C表写入该用户的UID和所投照片的PID
求助:
需要得出 CITY_ID (城市)=1 和 GROUP_ID (组别)=1 所投的总票数
------解决方案--------------------------------------------------------
- SQL code
SELECT COUNT(*) FROM A WHERE A.GROUP_ID = 1 AND A.CITY_ID = 1 AND A.UID IN (SELECT UID FROM C)
------解决方案--------------------------------------------------------
- SQL code
select count(*) from c,awhere c.uid=a.uidand a.city_id =1 and a.group_id = 1select count(*) from c where uid in (select uid from a where city_id =1 and group_id = 1)
------解决方案--------------------------------------------------------
select count(*) from c where uid in (select uid from a where group_id='1' and city_id='1')