mysql - 如何获得具有相同截止标记的行集？

Question

Name      Age      Cut-off
--------------------------
Ram       22        89.50
Ganesh    22        66.00
Sam       22        92.00
Albert    22        89.50
Kannan    22        65.45   
John      22        66.00

在上表中，Ram 和 Albert 以及 Ganesh 和 John 具有相同的截止值。我怎样才能得到所有这些行？

Answer 1

SELECT  a.*
FROM    tableName a
        INNER JOIN
        (
            SELECT `Cut-off`, COUNT(*) totalCOunt
            FROM    tableName
            GROUP   BY `Cut-off`
            HAVING  COUNT(*) > 1
        ) b ON a.`Cut-off` = b.`Cut-off`

为了获得更快的性能，请添加一个INDEXon 列Cut-off

• SQLFiddle 演示

Answer 2

这是一种方法：

select *
from t
where exists (select 1 from t t2 where t2.cutoff = t.cutoff and t2.name <> t.name)