使用 count 和 group_contat 后如何找到总数

Question

所以我制作了一个显示总数的表格，但总数不正确。

SQL 小提琴：http://sqlfiddle.com/#!9/de76b6e/12

预期输出：

ClientName	ClientPhone	Address	Services	Total
Chan Tai Man	12345678	82 Kennedy Street, Wan Chai	Carpets(2),Sofas(1)	1120
Wong Kai tung	28473465	24 Kennedy Road, Wan Chai	Mattresses(1)	100
Chan Tai Man	63827482	26 Queen Road East, Wan Chai	Carpets(1)	500

实际输出：

ClientName	ClientPhone	Address	Services	Total
Chan Tai Man	12345678	82 Kennedy Street, Wan Chai	Carpets(2),Sofas(1)	620
Wong Kai tung	28473465	24 Kennedy Road, Wan Chai	Mattresses(1)	100
Chan Tai Man	63827482	26 Queen Road East, Wan Chai	Carpets(1)	500

我的数据：

INSERT INTO MAIN VALUES( 
    null,'Carpets', '2021-03-09', '1');  
INSERT INTO MAIN VALUES( 
    null,'Sofas', '2021-03-09', '1');
INSERT INTO MAIN VALUES( 
    null,'Mattresses', '2021-03-10', '2');
INSERT INTO MAIN VALUES( 
    null,'Carpets', '2021-03-11', '3');
INSERT INTO MAIN VALUES( 
    null,'Carpets', '2021-03-11', '1');

  
 
/*****  CREATE SERVICE  **************************************************/
DROP TABLE IF EXISTS SERVICE;
CREATE TABLE SERVICE(
  ServiceName                       VarChar(20)   NOT NULL,
  CPS                               Numeric(20)   NOT NULL,
  CONSTRAINT          SERVICE_PK            PRIMARY KEY(ServiceName)
    );

/*****   SERVICE DATA   ***********************************************************/

INSERT INTO SERVICE VALUES('Carpets', 500);
INSERT INTO SERVICE VALUES('Sofas', 120);
INSERT INTO SERVICE VALUES('Mattresses', 100);
INSERT INTO SERVICE VALUES('Curtains', 80);



/*****   CREATE CLIENT   ***********************************************************/
DROP TABLE IF EXISTS CLIENT;
CREATE TABLE CLIENT (
    ClientID                            Int      auto_increment  NOT NULL,
    ClientName                      Char (50)           NOT NULL,
    ClientPhone                              Int (8)                    NOT NULL,
    Address                              VarChar(100)               NULL,
    CONSTRAINT        CLIENT_PK             PRIMARY KEY(ClientID)
    );

/*****   CLIENT DATA   *************************************************************/

INSERT INTO CLIENT VALUES(
    null,'Chan Tai Man', '12345678', '82 Kennedy Street, Wan Chai');
INSERT INTO CLIENT VALUES(
    null,'Wong Kai tung', '28473465', '24 Kennedy Road, Wan Chai');
INSERT INTO CLIENT VALUES(
    null,'Chan Tai Man', '63827482', '26 Queen Road East, Wan Chai');

/***********************************************************************************/

我的代码：

SELECT CLIENT.ClientName, CLIENT.ClientPhone, CLIENT.Address, 
GROUP_CONCAT(MAIN.Num) AS Services,
SUM(SERVICE.CPS) AS Total
FROM (
  SELECT DOS, InvoiceID, ClientID, ServiceName, 
  CONCAT(ServiceName, '(', count(ServiceName), ')') AS Num
  From MAIN
  GROUP BY ClientID, ServiceName
  ) MAIN
LEFT JOIN CLIENT ON MAIN.ClientID = CLIENT.ClientID 
LEFT JOIN SERVICE ON MAIN.ServiceName = SERVICE.ServiceName
GROUP BY CLIENT.ClientID
ORDER BY MAIN.DOS;

Answer 1

问题是您在汇总值之后进行 SUM。您应该对子查询中的服务表进行求和和 JOIN，例如：

SELECT CLIENT.ClientName, CLIENT.ClientPhone, CLIENT.Address, 
       GROUP_CONCAT(MAIN.Num) AS Services,
       sum(main.Total) as total
FROM (
  SELECT DOS, InvoiceID, ClientID, main.ServiceName, 
         CONCAT(main.ServiceName, '(', count(main.ServiceName), ')') AS Num,
         SUM(SERVICE.CPS) AS Total
  From MAIN
  LEFT JOIN SERVICE ON MAIN.ServiceName = SERVICE.ServiceName
  GROUP BY ClientID, ServiceName
  ) MAIN
LEFT JOIN CLIENT ON MAIN.ClientID = CLIENT.ClientID 
GROUP BY CLIENT.ClientID
ORDER BY MAIN.DOS;

除此之外，我不会使用与表名相同的名称作为别名