MySQL IF Statement¶

The MySQL allows you to execute a set of SQL statements based on a certain condiftion or value of an expression.

IF expression THEN 
   statements;
END IF;

If the expression evaluates to TRUE, then the statements will be executed.

MySQL IF-ELSE¶

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

MySQL IF-ELSEIF-ELSE¶

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

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$$