这个查询怎么做？

[krack2002]

table1其中的两个域为: userid、username
table2其中的两个域为: userid1、userid2(这两个域和table1中userid的关系都是多对1)

我想做一次查询后，得到userid1和userid2分别对应的username，这个查询怎么做？

[xelite]

--userid1对应的username
SELECT username
FROM table1,table2
WHERE table1.userid=table1.userid1

--userid2对应的类似

[hjb111]

select a.* from table2 a,table1 b where a.userid=b.userid and b.username=条件

[zarge]

select t1a.username, t1b.username
from table2 t2 inner join table1 t1a on t2.userid1 = t1a.userid
inner join table1 t1b on t2.userid2 = t1b.userid

[krack2002]

to xelite(潜龙):
这样分别查我会。我想问得是一次可否查询得到？怎样做这个视图？

[hjb111]

create view v_table2
as
select a.* from table2 a,table1 b where a.userid=b.userid and b.username=条件
Go

[txlicenhe]

select a.username,b.username
From table2 c
join table1 a on c.userid1 = a.userid
join table1 b on c.userid2 = b.userid

[dafu71]

SELECT username
FROM table1,table2
WHERE table1.userid=table2.userid1 or table1.userid=table2.userid2

[CrazyFor]

select a1.username,a2.username
from table2 b left join table1 a1 on b.userid1=a1.userid
left join table1 a2 on b.userid2=a2.userid