MySQL: stored procedure (SP)

DELIMITER $$

DROP PROCEDURE IF EXISTS spFoo $$
CREATE PROCEDURE spFoo ()
BEGIN
SELECT 'x' FROM xxx;
END $$

DELIMITER ;

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參數可以是IN, OUT, INOUT
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DELIMITER $$
DROP PROCEDURE IF EXISTS CountOrderByStatus$$CREATE PROCEDURE CountOrderByStatus(
 IN orderStatus VARCHAR(25),
 OUT total INT)
BEGIN
 SELECT count(orderNumber)
 INTO total
 FROM orders
 WHERE status = orderStatus;
END$$
DELIMITER ;

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獲得參數
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CALL CountOrderByStatus('Shipped',@total);
SELECT @total;