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UserID
1
2
3
4

Ò»¸öÊÇ´ÎÊýÁбí(ÿÌì·ÃÎÊÒ»´ÎNum+1)
UserID Day Num
1 2009-09-22  10
2 2009-09-22  20
4 2009-09-22  8

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2  20
1  10
4  8
3  0


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SQL code:
select t2.* from t1
left join t2 on t1.userid = t2.userid
order by t2.num desc

numÁвé³öÀ´µÄÖµÊÇNULLµÄÄã×Ô¼ºÔÙ´¦ÀíϾͿÉÒÔÁË¡£

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2Â¥µÄ»ù´¡ÉϼÓÉÏÅÅÐòµÄ¾Í¿ÉÒÔÁË.
select a.UserId as Userid,isnull(b.Num,0) as Num
from Óû§Áбí as a
left join ´ÎÊýÁбí as b
on a.UserId=b.UserId
order by b.Num desc

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select a.UserId as Userid,isnull(b.Num,0) as Num
from Óû§Áбí as a
left join ´ÎÊýÁбí as b
on a.UserId=b.UserId

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Èç¹ûÏëÊä³ö Óû§±í µÄÆäËû×ֶΠ¸ÃÔõô¸ÄÒ»ÏÂÄØ£¿

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¸ã¶¨ÁË£¬select a.UserId as Userid,isnull(b.Num,0) as Num
a.* from Óû§Áбí as a
left join ´ÎÊýÁбí as b
on a.UserId=b.UserId
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