MEMBER表字段
username password
111 111
222 222
333 333member_打卡表
username regdate(时间字段)
111
111
222
111
333
怎么样得到:
username password dkcount(打卡次数)
111 111 3
username password
111 111
222 222
333 333member_打卡表
username regdate(时间字段)
111
111
222
111
333
怎么样得到:
username password dkcount(打卡次数)
111 111 3
username password dkcount(打卡次数)
111 111 3
222 222 1
333 333 1
(
select username, count(regdate)
from member_打卡表
groub by username
)
select * from tb
inner join member on member.username = tb.username
select username, password, COUNT(*) AS DKCOUNT
from member
join 打卡表 on
member.username = 打卡表.username
GROUP BY USERNAME, PASSWORD
left join 能三表查询吗。。 还需要查一个表的count