MySQL 存儲過程中執行動態 SQL 語句

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)