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±í1 user (Óû§ÐÅÏ¢ )
username password
A 123
B 000
C 555
±í2 record (Óû§¼Ç¼)
id username logintime
1 C 2009-10-10
2 A 2009-10-11
3 A 2009-10-12
4 B 2009-10-13
5 B 2009-10-15
6 C 2009-10-16
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username password logintime
A 123 2009-10-12
B 000 2009-10-15
C 555 2009-10-16
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select username,password,(select top 1 logintime from record where record.username=[user].username order by logintime desc ) from [user]
select a.*,b.lasttime from user as a
left join
(select max(logintime)as lasttime,username from record group by username)
as b
on a.username = b.username
select t1.*,t2.lasttime from user t1
left join
(select username,max(logintime)as lasttime from record g
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date(Ö÷) outid(Ö÷) inid(Ö÷) num amt
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namespace AccessDb
{
public class AccessDbClass
{ ......