mysql的call用法 嵌套函数调用的例子

分享下mysql中call语句在嵌套函数中的用法。
代码：

mysql> DELIMITER //
mysql> CREATE FUNCTION myFunction (rush_ship INT(10)) RETURNS DECIMAL(10,2) //创建函数
    -> BEGIN
    ->
    -> DECLARE rush_shipping_cost DECIMAL(10,2);
    ->
    -> CASE rush_ship
    -> WHEN 1 THEN
    ->         SET rush_shipping_cost = 20.00;
    -> WHEN 2 THEN
    ->         SET rush_shipping_cost = 15.00;
    -> WHEN 3 THEN
    ->         SET rush_shipping_cost = 10.00;
    -> ELSE
    ->         SET rush_shipping_cost = 0.00;
    -> END CASE;
    ->
    -> RETURN rush_shipping_cost;
    ->
    -> END
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION myFunction1 (item_sum DECIMAL(10,2)) //创建函数
    -> RETURNS DECIMAL(10,1)
    -> BEGIN
    ->
    -> RETURN myFunction(1); //嵌套函数调用
    ->
    -> END
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;
mysql> select myFunction1(1); //调用函数
+----------------+
| myFunction1(1) |
+----------------+
|           20.0 |
+----------------+
1 row in set (0.00 sec)

mysql> drop function myFunction1; //删除mysql自定义函数
Query OK, 0 rows affected (0.00 sec)

mysql> drop function myFunction; //删除mysql自定义函数
Query OK, 0 rows affected (0.00 sec)