Question

I want to be able to compare 2 records in the same SQL table and tell if they are different. I do not need to tell what is different, just that they are different.

Also, I only need to compare 7 of 10 columns in the records. ie.) each record has 10 columns but I only care about 7 of these columns.

Can this be done through SQL or should I get the records in C# and hash them to see if they are different values?

Answer 1

You can write a group by query like this:

SELECT field1, field2, field3, .... field7, COUNT(*)
FROM table
[WHERE primary_key = key1 OR primary_key = key2]
GROUP BY field1, field2, field3, .... field7
HAVING COUNT(*) > 1

That way you get all records with same values for field 1 to 7, along with the number of occurrences.

Add the part between brackets to limit your search for duplicates, either with OR, or with IN (…).