SQL Server 比较同一表的两行的值并得到不匹配的列名

Question

I need to compare two rows ( INSERTED & DELETED ) of the same table and compare values. And then I need to get the not matching columns. Inside a trigger.

Here what I've tried so far but I 've no idea of how to compare these two rows and get column names which contains different values .

SELECT * 
FROM inserted i
INNER JOIN deleted d ON d.PurchasingDocItemNo = i.PurchasingDocItemNo 
                     AND d.PurchasingDocNo = i.PurchasingDocNo
                     AND d.ReferenceDocumentNo = i.ReferenceDocumentNo
                     AND d.ProductNo = i.ProductNo

Answer 1

Change your select to :

SELECT
-- For each column you're checking.  Also account for ISNull if you need to
CASE WHEN I.Col1 = D.Col1 THEN 0 ELSE 1 END AS Col1Changed.......
FROM INSERTED I
INNER JOIN DELETED D on (I.<PK> = D.<PK>)