本文介绍了视图的 SELECT 在 FROM 子句中包含子查询的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有两个表，我需要创建一个视图.这些表格是:
I have two tables and I need to create a view. The tables are:
credit_orders(id, client_id, number_of_credits, payment_status)
credit_usage(id, client_id, credits_used, date)
我使用以下查询来执行此操作.没有创建视图"部分的查询运行良好，但使用创建视图"时，它显示错误视图的 SELECT 包含 FROM 子句中的子查询".可能是什么问题&可能的解决方案:
I use the following query to do this. The query without the "create view" part works well but with "create view", it shows the error "View's SELECT contains a subquery in the FROM clause". What could be the issue & possible solution:
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)
推荐答案
根据文档:
MySQL 文档
- SELECT 语句不能在 FROM 子句中包含子查询.
您的解决方法是为每个子查询创建一个视图.
Your workaround would be to create a view for each of your subqueries.
然后从您的视图中访问这些视图 view_credit_status
Then access those views from within your view view_credit_status
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