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--½¨±ítable1,table2£º   
create table table1(id int,name varchar(10))   
create table table2(id int,score int)   
insert into table1 select 1,'lee'  
insert into table1 select 2,'zhang'  
insert into table1 select 4,'wang'  
insert into table2 select 1,90   
insert into table2 select 2,100   
insert into table2 select 3,70  
--½¨±ítable1,table2£º
create table table1(id int,name varchar(10))
create table table2(id int,score int)
insert into table1 select 1,'lee'
insert into table1 select 2,'zhang'
insert into table1 select 4,'wang'
insert into table2 select 1,90
insert into table2 select 2,100
insert into table2 select 3,70
Èç±í
-------------------------------------------------
table1|table2|
-------------------------------------------------
idname|idscore|
1lee|190|
2zhang|2100|
4wang|370|
-------------------------------------------------
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Sql´úÂë
select * from table1 left join table2 on table1.id=table2.id  
select * from table1 left join tab


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