Question

我的表：

id  | request |  subject     | date
1   |    5    |      1       |  576677
2   |    2    |      3       |  576698 
3   |    5    |      1       |  576999 
4   |    2    |      3       |  586999

需要通过两列（请求，主题）选择唯一记录，并显示最后插入的ID。

我的查询：

SELECT *,MAX(id) 
FROM `tbl` 
GROUP BY CONCAT(`request_id`, `subject_id`) 
HAVING (COUNT(`request_id`)>1 order by MAX(id) desc

但结果：

id  | request |  subject     | date
2   |    2    |      3       |  576698 
1   |    5    |      1       |  576677

如何获取ID为3和4的记录？

Answer 1

试试这个：

SELECT MIN(id) id, request, subject, MAX(`date`) `date`
FROM `tbl`
GROUP BY request, subject;

在SQL Fiddle上看到它。

Answer 2

你可以试试这个。

SELECT T.* 
FROM T
INNER JOIN 
(
    SELECT MAX(`ID`) as ID,`request`,`subject` 
    FROM T 
    GROUP BY `request`,`subject`
    HAVING COUNT(`ID`) > 1
)AS T1 ON T.ID = T1.ID

SQLFiddle

Answer 3

谢谢大家。我的结果是

SELECT MAX(id), id, request, subject, date
FROM `tbl`
GROUP BY request, subject having count(request)>1 order by MAX(id) desc

用两列在sql里面排序

3 个答案: