MySQL?? '?? SELECT? FROM ?? ?? ??? ???? ????' ??? ???? ??? ??????
Jan 04, 2025 am 05:58 AM
??: View? SELECT? FROM ?? ?? ??? ???? ????.
?? ??:
?? ????? ??? "?? SELECT ?? FROM? ???? ????"?? ??? ??????. ?? ?? ??". ???? ??? ??? ????.
create view view_credit_status as
(select credit_orders.client_id,
sum(credit_orders.number_of_credits) as purchased,
ifnull(t1.credits_used,0) as used
from credit_orders
left outer join (select * from (select credit_usage.client_id,
sum(credits_used) as credits_used
from credit_usage
group by credit_usage.client_id) as t0
) as t1 on t1.client_id = credit_orders.client_id
where credit_orders.payment_status='Paid'
group by credit_orders.client_id)
??:
MySQL ???? ??? SELECT ?? FROM ?? ?? ??? ??? ? ????.
???:
???? ? ?? ??? ?? ?? ??? ????. ?? ?? view_credit_status ???? ??? ??? ???? ? ????.
# 創(chuàng)建包含子查詢的視圖：
create view sum_credit_usage as
select client_id, sum(credits_used) as credits_used
from credit_usage
group by client_id;
# 創(chuàng)建您的最終視圖：
create view view_credit_status as
(select credit_orders.client_id,
sum(credit_orders.number_of_credits) as purchased,
ifnull(sum_credit_usage.credits_used, 0) as used
from credit_orders
left outer join sum_credit_usage on t1.client_id = credit_orders.client_id
where credit_orders.payment_status='Paid'
group by credit_orders.client_id);? ??? MySQL?? '?? SELECT? FROM ?? ?? ??? ???? ????' ??? ???? ??? ??????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!
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