Question

Column A | Column B (Beverage)
Andres      Coffee
Erica       Coffee
David       Beer
Tyler       Beer
Tyler       Beer
Andres      Shake
Erica       Coffee
Erica       Coffee
David       Beer
David       Coffee
Tyler       Water
Tyler       Shake

然后我只想看埃里卡和大卫（因为他们只有咖啡和/或啤酒），但不是安德列斯，因为他有摇晃;不是泰勒，因为他既有摇晃又有水。

Answer 1

您可以结合使用EXISTS和NOT EXISTS：

SELECT *
FROM YourTable AS T
WHERE EXISTS(SELECT 1 FROM YourTable
             WHERE ColumnA = T.ColumnA
             AND ColumnB IN ('Coffee','Beer'))
AND NOT EXISTS(SELECT 1 FROM YourTable
               WHERE ColumnA = T.ColumnA
               AND ColumnB IN ('Shake','Water'))

Answer 2

您可以使用not exists排除和区分以显示唯一的columnA

SELECT distinct ColA    FROM YourTable AS T
WHERE ColumnB IN ('Coffee','Beer')
AND NOT EXISTS(SELECT 1 FROM YourTable T2
               WHERE T2.ColumnA = T.ColumnA
               AND T2.ColumnB IN ('Shake','Water'))

Answer 3

简单GROUP BY。
不需要相关的子查询（存在/不存在）。

select      ColumnA    
from        mytable
group by    ColumnA
having      count (case when ColumnB in ('Coffee','Beer' ) then 1 end > 0
        and count (case when ColumnB in ('Water ','Shake') then 1 end = 0

Answer 4

   select columnA from t where columnB in ('Coffee','Beer')
      minus
   select columnA from t where columnB in ('Shake')
      minus
   select columnA from t where columnB in ('Shake','Water')
   having count(distinct columnB)=2
;

在这张表中，我如何才能让那些喝过咖啡或啤酒却从未有过摇晃或水的人回来？

4 个答案: