answer1:

ALTER TABLE old_table_name RENAME TO new_table_name;(大写为系统命令)

answer2:

sql> select tname from tab ;
TNAME
------------------------------
TEST

sql> rename test to temp ;
Table renamed.

sql> select tname from tab ;
TNAME
------------------------------
TEMP
rename只能修改自己schema下面的表。

answer3:

create new_table as select * from old_table;drop table old_table;

answer4:

直接在PLsql Developer里面改