mysql中的READS SQL DATA

CREATE PROCEDURE FILM_IN_STOCK(IN P_FILM_ID INT,IN P_STORE_ID INT , OUT P_FILM_COUNT INT)
-> READS SQL DATA
-> BEGIN
-> SELECT INVENTORY_ID
-> FROM INVENTORY
-> WHERE FILM_ID=P_FILM_ID
-> AND STORE_ID=P_STORE_ID
-> AND INVENTORY_IN_STOCK(INVENTORY_ID);
->
-> SELECT FOUND_ROWS() INTO P_FILM_COUNT;
-> END $$

READS SQL DATA 表示子程序包含讀數據的語句 但不包含寫數據的語句