我有以下查询：

select * from members,subscriptions

where members.MemberID = subscriptions.MemberID

and subscriptions.Year = 2009

and members.ASSCID = 15

and subscriptions.Untildate between '$2009-01-01' and '2009-12-31'

order by members.Memberlastname

会员支付其年度订阅费用一次(年度订阅),或者支付2次,一月份一次,六月份一次(六个月订阅).我想要的是拉至少支付一次的会员.

上面的声明会带来一些成员两次(那些在1月和6月均缴费的成员).

可以拉至少支付一次的会员(无论他们是支付年度订阅还是六个月订阅).避免重复.

解决方法:

成员表中的所有记录,其中每个成员至少具有一个订阅：

select members.*

from members join

(

select

members.MemberID, count(*)

from members join subscriptions on (members.MemberID = subscriptions.MemberID)

where subscriptions.Year = 2009

and subscriptions.Untildate between '2009-01-01' and '2009-12-31'

group by members.MemberID

having count(*) >= 1

)

v on ( members.MemberID = v.MemberID)

where members.ASSCID = 15

标签：unique,mysql

来源： https://codeday.me/bug/20191024/1919505.html