举例子:

hive> select * from zz0;
111111
222222
888888
hive> select * from zz1;
111111
333333
444444
888888

hive> select * from zz0 join zz1 on zz0.uid = zz1.uid;
111111  111111
888888  888888
hive> select * from zz0 left outer join zz1 on zz0.uid = zz1.uid;
111111  111111
222222  NULL
888888  888888
hive> select * from zz0 right outer join zz1 on zz0.uid = zz1.uid;
NULL
111111  111111
NULL    333333
NULL    444444
888888  888888
hive> select * from zz0 full outer join zz1 on zz0.uid = zz1.uid;
NULL
111111  111111
222222  NULL
NULL    333333
NULL    444444
888888  888888
hive> select * from zz0 left semi join zz1 on zz0.uid = zz1.uid;
111111  111111
888888  888888