IF search_condition THEN statement_list
[ELSEIF search_condition THEN statement_list] ...
[ELSE statement_list]
END IF
If statement checks a condition, running the statements in the block if the condition is true.
You can add ELSEIF statements to continue attempting to match conditions.
If desired, include a final ELSE statement.
mysql>
mysql> DELIMITER //
mysql> CREATE FUNCTION delivery_day_shipping (delivery_day INT(1)) RETURNS INT(2)
-> BEGIN
->
-> DECLARE shipping_cost INT(2) DEFAULT 0;
->
-> IF delivery_day = 1 THEN
-> SET shipping_cost = 20;
-> ELSEIF delivery_day = 2 THEN
-> SET shipping_cost = 15;
-> ELSEIF delivery_day = 3 THEN
-> SET shipping_cost = 10;
-> ELSE
-> SET shipping_cost = 5;
-> END IF;
->
-> RETURN shipping_cost;
->
-> END
-> //
ERROR 1304 (42000): FUNCTION delivery_day_shipping already exists
mysql> DELIMITER ;
mysql>