MySQL 存储过if语句用法

MySQL 存储过if语句用法，MySQL IF语句允许您根据表达式的某个条件或值结果来执行一组SQL语句。

 1，if 结构
    
		  IF expression THEN 
         statements;
    END IF;
			
			IF expression THEN

statements; ELSE else-statements; END IF;

IF expression THEN statements; ELSEIF elseif-expression THEN elseif-statements; ELSE else-statements; END IF;

	2，if实例
	
	DELIMITER $$

CREATE PROCEDURE GetCustomerLevel( in p_customerNumber int(11), out p_customerLevel varchar(10)) BEGIN DECLARE creditlim double;

SELECT creditlimit INTO creditlim
FROM customers
WHERE customerNumber = p_customerNumber;

IF creditlim > 50000 THEN

SET p_customerLevel = 'PLATINUM'; ELSEIF (creditlim <= 50000 AND creditlim >= 10000) THEN SET p_customerLevel = 'GOLD'; ELSEIF creditlim < 10000 THEN SET p_customerLevel = 'SILVER'; END IF;

END$$

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