一个SQL 语句的写法,该怎么处理

一个SQL 语句的写法
A:
r_id gametag_key gameclass_key
624
725
826
917
1028
1129
12210
13211

B:
r_id game_key
6264
6277
61
7276
72
83
94
105


要整合成

r_id gametag_key game_key
62264
62277
621
72276
722
823
914
1025


SQL 我是这样写的

SQL code

select  b.r_id,b.gametag_key,(select game_key from  B a )as game_key from A bwhere b.r_id=a.r_id

SQL code

select  b.r_id,b.gametag_key ,a.game_key from A b ,B a where b.r_id=a.r_id
[解决办法]
SQL code
select  b.*,a.gametag_key  from  (select a.r_id,a.gametag_key  from a)a,bwhere  a.r_id=b.r_id
[解决办法]
select a.r_id,a.gametag_key,b.game_key
from a
inner join b on a.r_id = b.r_id

[解决办法]
探讨

SQL code
select  b.r_id,b.gametag_key ,a.game_key from A b ,B a where b.r_id=a.r_id