求助sql高手，根据A表补全B表分组中的缺失记录

[lx_0409]

表A:
id name
1 a1
2 a2
3 a3
4 a4
5 a5

表B:
id name class score
1 a1 1 10
2 a2 1 20
3 a3 1 30
1 a1 2 15
4 a4 2 25

想得到的结果：
id name class score
1 a1 1 10
2 a2 1 20
3 a3 1 30
4 a4 1 0
5 a5 1 0
1 a1 2 15
2 a2 2 0
3 a3 2 0
4 a4 2 25
5 a5 2 0

[lx_0409]

加一点就对了,谢谢 with c as (select 1 class union all select 2) -- 班级表 select a.*, c.class, isnull(b.score,0) score from a , c left join b on a.id = b.id and a.class=b.class

[卖水果的net]

with c as (select 1 class union all select 2) -- 班级表 select a.*, c.class, isnull(b.score,0) score from a , c left join b on a.id = b.id