MySQL存储过程中实现执行动态SQL语句的方法

mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE set_col_value
  ->    (in_table   VARCHAR(128),
  ->     in_column  VARCHAR(128),
  ->     in_new_value VARCHAR(1000),
  ->     in_where   VARCHAR(4000))
  ->
  -> BEGIN
  ->  DECLARE l_sql VARCHAR(4000);
  ->  SET l_sql=CONCAT_ws(' ',
  ->        'UPDATE',in_table,
  ->          'SET',in_column,'=',in_new_value,
  ->        ' WHERE',in_where);
  ->  SET @sql=l_sql;
  ->  PREPARE s1 FROM @sql;
  ->  EXECUTE s1;
  ->  DEALLOCATE PREPARE s1;
  -> END$$
Query OK, 0 rows affected (0.00 sec)