比较一个表中2个列值的总和与第二个表SQL Server中另一个列的值

Question

我有两张桌子

table1（id，item，price）值：

id | item | price
-------------
10 | book | 20  
20 | copy | 30   
30 | pen  | 10

.... table2（id，item，price）值：

id | item | price
-------------
10 | book | 20
10 | book | 30

现在我如果在表1中没有id-10，item-book和price-（20 + 30）的记录，那么我想在新表中插入具有sum（20 + 30）的行...

Answer 1

尝试以下

SELECT T2.id,T2.item,T2.Price as Table2_Price,T1.Price as Table1_Price FROM (
SELECT id,Item,Sum(Price) as Price
FROM Table2
Group BY id,Item ) AS T2 LEFT JOIN Table1 AS T1
ON T1.Item = T2.Item and T1.ID = T2.ID

在读完注释后， when sum of these two not equals the one in another table it should return the sum from table 2 ，您需要以下逻辑

SELECT T2.id,T2.Item, CASE WHEN T1.Price IS NULL THEN T2.Price 
                           WHEN T2.Price <> T1.Price THEN T2.Price 
                           ELSE T1.Price END as Price FROM (
SELECT id,Item,Sum(Price) as Price
FROM Table2
Group BY id,Item ) AS T2 LEFT JOIN Table1 AS T1
ON T1.Item = T2.Item and T1.ID = T2.ID

但这逻辑没有用，因为如果Sum(Table2_price) <> Table1_Price您想选择Sum(Table2_price)否则当Sum(Table2_price) = Table1_Price您想要Table1_Price ！ 所以您要始终选择Sum(Table2_Price)

Answer 2

如果我没有误解您的要求，可以这样做：

 SELECT T2.ID, T2.ITEM,T2.SUMPRICE FROM 
 (SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table1 GROUP BY ID, ITEM) AS T1
 INNER JOIN 
 (SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table2 GROUP BY ID, ITEM) AS T2
 ON T1.ID = T2.id  AND T1.item = T2.item WHERE T1.SUMPRICE <> T2.SUMPRICE 

如果已经创建了第三个表，则可以使用INSERT INTO SELECT语句。 否则，您可以像这样使用SELECT INTO ：

SELECT T2.ID, T2.ITEM,T2.SUMPRICE as price into table3 FROM 
(SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table1 GROUP BY ID, ITEM) AS 
T1
INNER JOIN 
(SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table2 GROUP BY ID, ITEM) AS 
T2
ON T1.ID = T2.id  AND T1.item = T2.item WHERE T1.SUMPRICE <> T2.SUMPRICE 

希望能帮助到你！

编辑1如果要获取所有不匹配的行，即：

1. 表2中ID，商品或价格与表1中给定行同时不匹配的行
2. 表2中的行，其中没有任何列与表1中的给定行同时匹配

您可以使用EXCEPT语句，例如：

(SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table2 GROUP BY ID, ITEM) 
 EXCEPT
(SELECT ID, ITEM, SUM(PRICE) AS SUMPRICE FROM table1 GROUP BY ID, ITEM) 

返回：

ID   ITEM                 SUMPRICE
---- -------------------- -----------
10   book                 50