SQL服务器操作情况下，当我where子句

Question

我有一个看起来简单像这样的SQL Server存储过程：

begin 

select 
(
case 
    when @Method = 'phone' then u.PhoneNumber 
    when @Method = 'email' then u.Email 
end 
) 
from 
    Table a 
join 
    Users u on a.ID = u.Id 
where 
    a.Active = 1 
    and 

    -- This part does not work 
    case 
     when @Method = 'phone' then u.PhoneNumber is not null 
     when @Method = 'email' then u.Email is not null 
    end 
end 

所以问题是，我不想空值和两个电话和电子邮件可以空值。因此，如果@Method参数是手机，我不希望u.PhoneNumber中的空值，并且当输入参数是电子邮件时，我不希望u.Email列中的值为空值。

解决此问题的最佳方法是什么？

Answer 1

更改其中条件如下

where 
a.Active = 1 
and (
    (@Method = 'phone' and u.PhoneNumber is not null) 
    or 
    (@Method = 'email' and u.Email is not null) 
    ) 

Answer 2

你不需要使用情况时，你可以使用

where 
a.Active = 1 
and 

-- This part now work 
(
    (@Method = 'phone' and u.PhoneNumber is not null) OR 
    (@Method = 'email' and u.Email is not null) 
) 

Answer 3

它就像你的SELECT语句

where 
a.Active = 1 
and 
case 
    when @Method = 'phone' then u.PhoneNumber 
    when @Method = 'email' then u.Email 
end is not null