Using Declare statement to declare the local variable : Variable Scope « Procedure Function « MySQL Tutorial

1. MySQL Tutorial
2. Procedure Function
3. Variable Scope

mysql>
mysql> DELIMITER //
mysql>
mysql> CREATE FUNCTION myFunction (cost DECIMAL(10,2)) RETURNS DECIMAL(10,2)
    -> BEGIN
    ->
    ->     DECLARE shipping_cost DECIMAL(10,2);
    ->
    ->     SET shipping_cost = 0;
    ->     IF cost < 25.00 THEN
    ->             SET shipping_cost = 10.00;
    ->     ELSEIF cost < 100.00 THEN
    ->             SET shipping_cost = 20.00;
    ->     ELSEIF cost < 200.00 THEN
    ->             SET shipping_cost = 30.00;
    ->
    ->     ELSE
    ->             SET shipping_cost = 40.00;
    ->     END IF;
    ->
    ->     RETURN shipping_cost;
    -> END
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;
mysql>
mysql> select myFunction(123.123);
+---------------------+
| myFunction(123.123) |
+---------------------+
|               30.00 |
+---------------------+
1 row in set, 1 warning (0.02 sec)

mysql>
mysql> drop function myFunction;
Query OK, 0 rows affected (0.00 sec)