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

I have two tables...

table1 ( id, item, price ) values:

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

....table2 ( id, item, price) values:

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

now i if do not have a record with id-10,item-book and price-(20+30) in table 1 then i want to insert that row with sum(20+30) in a new table ...

Answer 1

Try the following

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

After reading your comments when sum of these two not equals the one in another table it should return the sum from table 2 , you are asking for the following logic

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

But this logic isn't useful, because if Sum(Table2_price) <> Table1_Price you want to select Sum(Table2_price) else when Sum(Table2_price) = Table1_Price you want Table1_Price !! So you want to always choose Sum(Table2_Price)

Answer 2

If I haven't misunderstood your requirements, this should do it:

 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 

If your 3rd table is already created you could just use an INSERT INTO SELECT statement. Otherwise you could use a SELECT INTO like this:

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 

Hope it helps!

EDIT 1 In the case that you want to get all the unmatched rows, that is:

1. Rows from table 2 where the id, item or price don't match simultenously with a given row in table 1
2. Rows from table 2 where none of their columns match simultenously with a given row in table 1

You could use the EXCEPT statement, for example:

(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) 

This returns:

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