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我有一个烦人的 SQL 语句，看起来很简单，但看起来很糟糕。我希望 sql 返回一个用户数据排序的结果集，以便某个用户是结果集中的第一行，如果该用户的电子邮件地址在公司表中。

我有这个返回我想要的 SQL，但我认为它看起来很糟糕：

select 1 as o, * 
from Users u
where companyid = 1
and email = (select email from companies where id=1)
union 
select 2 as o, * 
from Users u
where companyid = 1
and email <> (select email from companies where id=1)
order by o

顺便说一句，用户表中的电子邮件地址可以在许多公司中，因此不能在电子邮件地址上加入:-(

你有什么想法可以改进这个陈述吗？

我正在使用 Microsoft SQL Server 2000。

编辑：我使用这个：

select *, case when u.email=(select email from companies where Id=1) then 1 else 2 end AS SortMeFirst 
from Users u 
where u.companyId=1 
order by SortMeFirst

它比我的更优雅。谢谢理查德 L！

4

3 回答 3

6

你可以做这样的事情..

        select CASE 
                WHEN exists (select email from companies c where c.Id = u.ID and c.Email = u.Email) THEN 1 
                ELSE 2 END as SortMeFirst,   * 
    From Users u 
    where companyId = 1 
    order by SortMeFirst
于 2009-01-28T13:02:13.300 回答
5

这会工作吗？：

select c.email, * 
from Users u
     LEFT JOIN companies c on u.email = c.email
where companyid = 1
order by c.email desc
-- order by case when c.email is null then 0 else 1 end
于 2009-01-28T12:57:48.787 回答
1

我不确定这会更好，但这是一种替代方法

select *, (select count(*) from companies where email = u.email) as o 
from users u 
order by o desc

编辑：如果不同公司之间可以有许多匹配的电子邮件，并且您只对给定的公司感兴趣，那么这就变成了

select *, 
 (select count(*) from companies c where c.email = u.email and c.id = 1) as o 
from users u 
where companyid = 1
order by o desc
于 2009-01-28T12:57:52.420 回答