程序限制

Question

我需要帮助！我试着寻找答案但没有找到任何答案。

我正在使用MYSQL6。

我所做的是创建2个视图，我想限制这些视图以获得通过函数计算的特定数量的结果。

功能：

DELIMITER $$

    CREATE FUNCTION `get_total_customers`() RETURNS int(11)
BEGIN

DECLARE TotalCustomers INT;

SELECT (count(customer_id)*0.2) INTO TotalCustomers FROM customer;

RETURN TotalCustomers;
END

---

VIEW1：

    CREATE VIEW PreferredStatus AS 
SELECT customer_id, SUM(amount) AS TotalAmount, get_total_customers() AS Total FROM payment
GROUP BY customer_id 
ORDER BY TotalAmount DESC;

---

视图2：

    CREATE VIEW RegularStatus AS
SELECT customer_id, SUM(amount) AS TotalAmount, get_total_customers() AS Total FROM payment
GROUP BY customer_id 
ORDER BY TotalAmount ASC
LIMIT Total;

这是使用视图的过程。

 > DELIMITER $$

CREATE PROCEDURE `CustomerStatus`(in custID int, out status varchar(200))
BEGIN

declare number1 int;
declare totalvar int;
declare limit2 int;

IF custID in (SELECT customer_id FROM PreferredStatus) THEN 
    set status = "preferred";

ELSEIF custID in (SELECT customer_id FROM RegularStatus) THEN  
    set status = "casual";

ELSE
    set status = "regular";

End If; 
END

---

请帮忙！

-Thanks。

Answer 1

您可以将LIMIT添加到创建SELECT的{​​{1}}：

VIEW

sqlfiddle demo

来自the docs的警告：

  

如果视图定义包含LIMIT子句，则从中选择   查看使用具有自己的LIMIT子句的语句，它是未定义的   适用的限制。