这个SELECT语句不会写？

Question

数据表：Table1
字段：   HideNO    CreatDate
         20055     2007-01-04 08:10:20
         20055     2007-01-04 09:10:20
         20055     2007-01-05 08:10:20
         20023     2007-01-07 10:10:20
         20023     2007-01-03 08:10:20
           ....    ......最后想得到结果为：
字段：   HideNO    CreatDate
         20055     2007-01-04 08:10:20
         20023     2007-01-07 10:10:20
         .....     ...............
这个Select 语句怎么写？

Answer 1

select HideNO , min(CreatDate) as CreatDate
from Table1
group by HideNO

Answer 2

SELECT HideNO,MIN(CreatDate) FROM Table1 GROUP BY HideNO

Answer 3

Select HideNO,MIN(CreatDate) From Table1 Group By HideNO

Answer 4

select * from Table1  t where table1.createdate =(select min(createdate) from table1 where hideNO=t.hideno)这样写的好处是便于扩展
也就是如果你是HIDEID，还有其他字段来决定我想要的最新时间的话
这个就有优势了

Answer 5

数据表：Table1
字段：   HideNO    CreatDate
         20055     2007-01-04 08:10:20
         20055     2007-01-04 09:10:20
         20055     2007-01-05 08:10:20
         20023     2007-01-07 10:10:20
         20023     2007-01-03 08:10:20
           ....    ......最后想得到结果为：
字段：   HideNO    CreatDate
         20055     2007-01-04 08:10:20
         20023     2007-01-07 10:10:20    ------这一句
         .....     ...............
结果有些问题
道底是要最近时间,还是最晚时间select HideNO , min(CreatDate) as CreatDate
from Table1
group by HideNo
执行的结果是
HideNO                                             CreatDate
-------------------------------------------------- -----------------------
20023                                              2007-01-03 08:10:20.000
20055                                              2007-01-04 08:10:20.000(2 行受影响)
select HideNO , max(CreatDate) as CreatDate
from Table1
group by HideNo
执行的结果是HideNO                                             CreatDate
-------------------------------------------------- -----------------------
20023                                              2007-01-07 10:10:20.000
20055                                              2007-01-05 08:10:20.000不知道楼主的答案是如何得到

Answer 6

谢谢，楼上的！
再说一下，如果子CreatDate字段不是日期，是其它字符型 怎么写？

Answer 7

不是也一样,取得最小值;select HideNO , min(CreatDate) as CreatDate
from Table1
group by HideNO