Consider two rows with id m and n in a table tb with a column cl, what's the sql command to set the value of cl in row n the same as that in row m?
Below is my testing mysql> desc student; +-------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | name | varchar(32) | YES | | NULL | | | gpa | decimal(2,1) | YES | | NULL | | +-------+--------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec) mysql> select * from student; +----+--------+------+ | id | name | gpa | +----+--------+------+ | 1 | Bob | 4.0 | | 2 | Ming | 3.8 | | 3 | Ann | 3.8 | | 4 | Howe | 3.8 | | 5 | nobody | 3.8 | +----+--------+------+ 5 rows in set (0.00 sec) mysql> update student set gpa = (select gpa from student where id=1) where id=5; ERROR 1093 (HY000): You can't specify target table 'student' for update in FROM clause mysql> -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
