Question

这就是我的表格：

╔══════╦═══════╗
║ USER ║ COLOR ║
╠══════╬═══════╣
║ a    ║ Red   ║
║ b    ║ Blue  ║
║ c    ║ Blue  ║
║ b    ║ Red   ║
║ a    ║ Red   ║
║ c    ║ White ║
╚══════╩═══════╝

我只需要独占 color =“Red”的行。
它必须返回“a”（“b”也包含值“Blue”）。

如何设置选择？

Answer 1

您可以使用：

select *
from yourtable t1
where color = 'red'
  and exists (select user
              from yourtable t2
              where t1.user = t2.user
              group by user
              having count(distinct color) = 1)

请参阅SQL Fiddle with Demo

或者没有子查询，您可以使用：

select *
from yourtable
group by user
HAVING  SUM(color = 'red') = COUNT(*)

请参阅SQL Fiddle with Demo

Answer 2

尝试他的查询

Select * 
from tbl 
where color = 'RED' AND USER not in 
(Select USER from tbl where color <> 'RED');

如何选择只有一个值的行？

2 个答案: