如何对具有多个值的多列求和 [英] How to Sum multiple Column with multiple value

问题描述

我正在寻找以下解决方案:

1. 进入用户表，找到在站点上列出项目的用户.在此用户表中，没有关于拍卖的列.而是使用键将其连接到帐户表(在帐户中，此列称为用户)

2. 从这些ID(列出了要拍卖物品的用户)中，我需要找到其帐户余额.这也在帐户表中.余额包含在名为operation_amount的列中.我还有另一列称为operation_type的列，它描述用户的余额是正数还是负数.例如，如果operation_type = 1，则其余额为负；而如果operation_type = 2，则其余额为正.

现在，我有另一个名为tmpinvoice的表，其中有一个称为金额的列.这显示了用户需要向站点管理员支付多少费用.

鉴于此，我需要计算他必须支付的总金额.例如，如果用户有200美元的余额，我需要根据operation_type检查它是负数还是正数.

所以我有一个查询，在哪里执行此操作仅用于记录

SELECT u.id AS id_user, u.nick,
  CASE ac.operation_type WHEN 1 THEN ac.operation_amount - tm.amount
                         WHEN 2 THEN ac.operation_amount + tm.amount
                                ELSE 'N/A' END AS `fee`                         
FROM auctionbg_search.accounts AS ac    
    LEFT JOIN auctionbg_search.users AS u ON TRUE
        AND u.id = ac.user
    LEFT JOIN auctionbg_search.auctions AS a ON TRUE
        AND a.id = ac.auction
    LEFT JOIN auctionbg_search.tmpinvoice AS tm  ON TRUE    
WHERE TRUE
  AND tm.amount = ac.operation_amount

这是我收到的结果

http://gyazo.com/3d7e7f52ee14d21cc8c8d33b6bbc479a

是的，但这仅针对列中的1个值计算费用"，如果用户有多个值怎么办

喜欢该用户:

http://gyazo.com/c3bdb29fa235044ab888dc0385bbcdbd

我需要根据该给定用户的operation_amount计算总金额，并从该总金额中删除tmpinvoice，

我的一个朋友告诉我使用

IF(SUM(ac.operation_amount), IS NULL , 0, sum(ac.operation_amount) 

，并使用+和-

两种情况加入2个时间账户(表)

加入1次+，2次--p

但我不知道它的外观如何:)

解决方案

在SUM函数中使用CASE表达式.

   SELECT u.id AS id_user, u.nick,
     SUM(CASE ac.operation_type WHEN 1 THEN ac.operation_amount - tm.amount У
                                WHEN 2 THEN ac.operation_amount + tm.amount
                                       ELSE 'N/A' END) AS `fee`
    FROM auctionbg_search.accounts AS ac
      LEFT JOIN auctionbg_search.users AS u ON TRUE AND u.id = ac.user 
      LEFT JOIN auctionbg_search.auctions AS a ON TRUE AND a.id = ac.auction
      LEFT JOIN auctionbg_search.tmpinvoice AS tm  ON TRUE  
    WHERE TRUE AND tm.amount = ac.operation_amount
    GROUP BY u.id, u.nick       

在 SQLFiddle

上查看演示

I am looking for a solution to the following:

1. Go in to the users table and find a user who has listed items on the site. In this users table, there is no column about auctions. Instead, it is connected to an accounts table with a key (in accounts, this column is called user)

2. From these IDs (users which have listed items for auction), I need to find their account balance. This is also in the accounts table. The balance is contained in a column called operation_amount. I also have another column called operation_type which describes whether a user has a positive or negative balance. For example, if operation_type = 1, he has a negative balance, while if operation_type = 2, he has a positive balance.

Now I have another table called tmpinvoice where there is a column called amount. This shows how much in fees a user needs to pay to the site administrators.

Given this, I need to calculate how much he must pay in total. For example, if a user has a $200 balance, I need to check whether it's negative or positive based on the operation_type.

So I have query where is Do this only for record

SELECT u.id AS id_user, u.nick,
  CASE ac.operation_type WHEN 1 THEN ac.operation_amount - tm.amount
                         WHEN 2 THEN ac.operation_amount + tm.amount
                                ELSE 'N/A' END AS `fee`                         
FROM auctionbg_search.accounts AS ac    
    LEFT JOIN auctionbg_search.users AS u ON TRUE
        AND u.id = ac.user
    LEFT JOIN auctionbg_search.auctions AS a ON TRUE
        AND a.id = ac.auction
    LEFT JOIN auctionbg_search.tmpinvoice AS tm  ON TRUE    
WHERE TRUE
  AND tm.amount = ac.operation_amount

Here what result I'm receiving

http://gyazo.com/3d7e7f52ee14d21cc8c8d33b6bbc479a

Yes but this calculate 'fee' only for 1 value in column , what if user have multiple values

like this user :

http://gyazo.com/c3bdb29fa235044ab888dc0385bbcdbd

I need calculate total amount from operation_amount of that given user and remove tmpinvoice from that total amount ,

A friend of mine told me to use

IF(SUM(ac.operation_amount), IS NULL , 0, sum(ac.operation_amount) 

and to join 2 time accounts(table) for both case with + and -

join 1 time for + , 2 time for -

but I can't figure out how will looks :)

解决方案

Use CASE expression within the SUM function.

   SELECT u.id AS id_user, u.nick,
     SUM(CASE ac.operation_type WHEN 1 THEN ac.operation_amount - tm.amount У
                                WHEN 2 THEN ac.operation_amount + tm.amount
                                       ELSE 'N/A' END) AS `fee`
    FROM auctionbg_search.accounts AS ac
      LEFT JOIN auctionbg_search.users AS u ON TRUE AND u.id = ac.user 
      LEFT JOIN auctionbg_search.auctions AS a ON TRUE AND a.id = ac.auction
      LEFT JOIN auctionbg_search.tmpinvoice AS tm  ON TRUE  
    WHERE TRUE AND tm.amount = ac.operation_amount
    GROUP BY u.id, u.nick       

See demo on SQLFiddle

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