sqlÇóд·¨

sqlÇóд·¨
±í£±£º
×Ö¶ÎÃû:f1 f2
      1  b1
      2  b2
      3  b3
±í2:
×Ö¶ÎÃû:f1 f2 f3
      1  c1  1
      1  c2  2
      2  c3  1
ÎÒÏëÁ½Õűíͨ¹ýf1×Ö¶ÎÁ¬³ÉÈçÏÂЧ¹û
1 b1 c2  2
2 b2 c3  1
3 b3 null null     

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SQL code:
select a.*,b.f2,b.f3 from ±í1 a left join ±í2 b on a.f1=b.f1

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SQL code:
select t1.*,t2.f2,t2.f3
from t1
left join t2 on t1.f1=t2.f1

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û¿´Ã÷°×ʲô¹Øϵ

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SQL code:
select * from ±í£± as a,±í2 as b where a.f1=b.f1

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SQL code:
select isnull(m.f1,n.f1) f1 , n.f2 , n.f3 from tb1 m left join
(select t.* from tb2 t where f3 = (select max(f3) from tb2 where f1 = t.f1)) n
on m.f1 = n.f1

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SQL code

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