# a 表
hive> select * from a;
1 a
2 b
5 e
6 f
# b 表
hive> select * from b;
1 a
2 b
3 c
4 d
# 内连接 join
hive> select * from a join b on a.key=b.key;
1 a 1 a
2 b 2 b
# 左外连接 left outer join
hive> select * from a left outer join b on a.key = b.key;
1 a 1 a
2 b 2 b
5 e NULL NULL
6 f NULL NULL
# 右外连接 right outer join
hive> select * from a right outer join b on a.key = b.key;
1 a 1 a
2 b 2 b
NULL NULL 3 c
NULL NULL 4 d
# 全外连接 full outer join
hive> select * from a full outer join b on a.key = b.key;
1 a 1 a
2 b 2 b
NULL NULL 3 c
NULL NULL 4 d
5 e NULL NULL
6 f NULL NULL
# 左半连接 left semi join
hive> select * from a left semi join b on a.key = b.key;
1 a
2 b