[Mysql] Update Select

UPDATE TABLE_A A, TABLE_B B

       SET A.COLUMN_1 = B.COLUMN_2

  WHERE A.COLUMN_3 = B.COLUMN_5;

UPDATE TABLE_A A 

     LEFT JOIN TABLE_B B 

        ON A.COLUMN_1= B.COLUMN_2 

       SET A.COLUMN = COLUMN_2

  WHERE A.COLUMN2 IS NULL

출처 : http://dev.mysql.com/doc/refman/5.0/en/update.html