一个表里有type字段和时间字段(存的时间) 存的都是 1 2 3 这样的类别值如何每一个类别取出前2条(时间倒序排的)一公5个类别 1 2 3 4 5 type |date
1 | 2006-10-1 12:12:10
1 | 2006-10-1 12:12:11
1 | 2006-10-1 12:12:12
2 | 2006-10-1 12:12:10
2 | 2006-10-1 12:12:11
2 | 2006-10-1 12:12:12
3 | 2006-10-1 12:12:10
3 | 2006-10-1 12:12:11
3 | 2006-10-1 12:12:12
4 | 2006-10-1 12:12:10
4 | 2006-10-1 12:12:11
4 | 2006-10-1 12:12:12
5 | 2006-10-1 12:12:10
5 | 2006-10-1 12:12:11
5 | 2006-10-1 12:12:12想要得到 type |date
1 | 2006-10-1 12:12:11
1 | 2006-10-1 12:12:12
2 | 2006-10-1 12:12:11
2 | 2006-10-1 12:12:12
3 | 2006-10-1 12:12:11
3 | 2006-10-1 12:12:12
4 | 2006-10-1 12:12:11
4 | 2006-10-1 12:12:12
5 | 2006-10-1 12:12:11
5 | 2006-10-1 12:12:12
1 | 2006-10-1 12:12:10
1 | 2006-10-1 12:12:11
1 | 2006-10-1 12:12:12
2 | 2006-10-1 12:12:10
2 | 2006-10-1 12:12:11
2 | 2006-10-1 12:12:12
3 | 2006-10-1 12:12:10
3 | 2006-10-1 12:12:11
3 | 2006-10-1 12:12:12
4 | 2006-10-1 12:12:10
4 | 2006-10-1 12:12:11
4 | 2006-10-1 12:12:12
5 | 2006-10-1 12:12:10
5 | 2006-10-1 12:12:11
5 | 2006-10-1 12:12:12想要得到 type |date
1 | 2006-10-1 12:12:11
1 | 2006-10-1 12:12:12
2 | 2006-10-1 12:12:11
2 | 2006-10-1 12:12:12
3 | 2006-10-1 12:12:11
3 | 2006-10-1 12:12:12
4 | 2006-10-1 12:12:11
4 | 2006-10-1 12:12:12
5 | 2006-10-1 12:12:11
5 | 2006-10-1 12:12:12
select type,date from b as a
where date in
(select top 2 date from b as c
where a.type=c.type)
已测试