这是对优秀答案的后续问题:
SQL Select only rows with Max Value on a Column
SQLFiddlehttp://sqlfiddle.com/#!2/3077f/2
表“yourtable”:

| id | val | ignore | content |
-------------------------------
| 1  | 10  |   0    |   A     |
| 1  | 20  |   0    |   B     |
| 1  | 30  |   1    |   C     |
| 2  | 40  |   0    |   D     |
| 2  | 50  |   0    |   E     |
| 2  | 60  |   1    |   F     |

查找每个id的最大值时,使用以下sql:
select yt1.*
from yourtable yt1
left outer join yourtable yt2
on (yt1.id = yt2.id and yt1.val < yt2.val )
where yt2.id is null;

所以在这种情况下
| id | val | ignore | content |
-------------------------------
| 1  | 30  |   1    |   C     |
| 2  | 60  |   1    |   F     |

问题是当它等于1时,如何按“忽略”列过滤,结果将是
| id | val | ignore | content |
-------------------------------
| 1  | 20  |   0    |   B     |
| 2  | 50  |   0    |   E     |

最佳答案

您需要将条件同时放入子查询和外部查询中:

select yt1.*
from yourtable yt1 left outer join
     yourtable yt2
     on yt1.id = yt2.id and yt1.val < yt2.val and yt2.ignore <> 1
where yt2.id is null and yt1.ignore <> 1;

关于mysql - SQL仅选择按列过滤的列中具有最大值的行,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/25245008/

10-13 06:56