第23章 使用存储过程

DELIMITER ;;

CREATE PROCEDURE ordertotal(
    IN onumber INT,
    IN taxable DECIMAL(8,2),
    OUT ototal DECIMAL(8,2)
) COMMENT 'Obtain order total, optionally adding tax'
BEGIN
    -- Declare variable for total
    DECLARE total DECIMAL(8,2);
    -- Declare tax percantage
    DECLARE taxrate INT DEFAULT 6;

    -- Get the order total
    SELECT SUM(item_price*quantity)
    FROM orderitems
    WHERE order_num = onumber
    INTO total;

    -- Is this taxable?
    IF taxable THEN
        SELECT total+(total/100*taxrate) INTO total;
    END IF;

    SELECT total INTO ototal;
END;;

DELIMITER ;


CALL ordertotal(20005, 1, @total);
SELECT @total;

第24章

DELIMITER ;;

CREATE PROCEDURE processorders()
BEGIN
    -- Declare local variables
    DECLARE done BOOLEAN DEFAULT 0;
    DECLARE o INT;
    DECLARE t DECIMAL(8,2);
    
    -- Declare the cursor
    DECLARE ordernumbers CURSOR
    FOR
    SELECT order_num FROM orders;

    -- Declare continue handler
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done=1;

    -- Create a table to store the results
    CREATE TABLE IF NOT EXISTS ordertotals(
        order_num INT,
        total DECIMAL(8,2)
    );

    -- Open the cursor
    OPEN ordernumbers;

    -- Loop through all rows
    REPEAT
        -- Get order number
        FETCH ordernumbers INTO o;

        -- Get the total for this order
        CALL ordertotal(o, 1, t);

        -- Insert order and total into ordertotals
        INSERT INTO ordertotals(order_num, total)
        VALUES(o, t);
    UNTIL done END REPEAT;
    
    -- Close the cursor
    CLOSE ordernumbers;
END;;

DELIMITER ;


CALL processorders();
SELECT * FROM ordertotals;