SQL where子句具有多个条件

Question

在我的数据库表中，我有一些像上面的图像。

我想查看where子句中的一些条件。

我想通过网址检查

1. DemoOrPaid=PAID and ValidUpto=NULL => then Return 1 2。DemoOrPaid=PAID and ValidUpto=(NOT NULL) then compare with current date and check if ValidUpto<=GETDATE() => then Return 1
2. DemoOrPaid=DEMO and ValidUpto=NULL => then Return 0
3. DemoOrPaid=DEMO and ValidUpto=(NOT NULL) then compare with current date and check if ValidUpto<=GETDATE() => then Return 0

Answer 1

如果要返回某些计算列，则可以使用以下内容：

select
    case
        when DemoOrPaid = 'PAID' and ValidUpto is null then 1
        when DemoOrPaid = 'PAID' and ValidUpto is not null and ValidUpto <= getdate() then 1
        when DemoOrPaid = 'DEMO' and ValidUpto is null then 1
        else 0
    end

实际上有点不清楚在您的条件未涵盖的情况下您想要返回什么。

Answer 2

以下内容将返回匹配的所有行。

select * from Table where 
(DemoOrPaid='PAID' and ValidUpto is NULL) or 
(DemoOrPaid='PAID' and ValidUpto is NOT NULL and ValidUpto<=GETDATE()) or 
(DemoOrPaid='DEMO' and ValidUpto is NULL) or 
(DemoOrPaid='DEMO' and ValidUpto is NULL and ValidUpto<=GETDATE())