Get column name where values differ between two rows - sql

Question

I have a table with lots of columns. Sometimes I need to find differences between two rows. I can do it just by scrolling through screen but it is dull. I'm looking for a query that will do this for me, something like
SELECT columns_for_id_1 != columns_for_id_2
FROM xyz
WHERE id in (1,2)
Table:
id col1 col2 col3 col4
1 qqq www eee rrr
2 qqq www XXX rrr
Result:
"Different columns: id, col3"
Is there a simple way to do this?
UPDATE
Another example as wanted:
What I have (table has more than 50 column, not only 7):
Id| Col1 | Col2 | Col3 | Col4 | Col5 | Col6 |
==============================================
1 | aaa | bbb | ccc | ddd | eee | fff |
----------------------------------------------
2 | aaa | XXX | ccc | YYY | eee | fff |
Query:
SELECT *
FROM table
WHERE Id = 1 OR Id = 2
AND "columns value differs"
Query result: "Id, Col2, Col4"
OR something like:
Id|Col2 |Col4 |
===============
1 |bbb |ddd |
---------------
2 |XXX |YYY |
Right now I have to scroll through more than 50 columns to see if rows are the same, it's not efficient and prone to mistakes. I don't want any long query like
SELECT (COMPARE Id1.Col1 with Id2.Col1 if different then print "Col1 differs", COMPARE Id1.Col2 with Id2.Col2...) because I will compare the rows myself faster ;)

Answer 1

Something like this:
SELECT col, MIN(VAL) AS val1, MAX(val) AS val2
FROM (
SELECT id, val, col
FROM (
SELECT id, [col1], [col2], [col3], [col4]
FROM mytable
WHERE id IN (1,2)) AS src
UNPIVOT (
val FOR col IN ([col1], [col2], [col3], [col4])) AS unpvt ) AS t
GROUP BY col
HAVING MIN(val) <> MAX(val)
Output:
col val1 val2
================
col3 eee XXX

Answer 2

Try this simple query, may be help you
SELECT (CASE WHEN a.col1 <> b.col1 THEN 'Different Col1'
WHEN a.col2 <> b.col2 THEN 'Different Col2'
...
ELSE 'No Different' END) --You can add only required columns here
FROM xyz AS a
INNER JOIN xyz AS b ON b.id = 1 --First Record
WHERE a.id = 2 --Second record to compare

Answer 3

If you are on SQL Server 2012 then you can also use LEAD/LAG windowed funuction to do this. MSDN Reference is here - https://msdn.microsoft.com/en-us/library/hh213125.aspx
select
id,
col1,
col2,
col3,
col4,
stuff(diff_cols,len(diff_cols-1),1,'') diff_cols
from
(
SELECT
id,
col1,
col2,
col3,
col4,
concat
(
'Different columns:',
CASE
WHEN LEAD(id, 1,0) OVER (ORDER BY id) <> id THEN 'id,'
WHEN LEAD(col1, 1,0) OVER (ORDER BY id) <> col1 THEN 'col1,'
WHEN LEAD(col2, 1,0) OVER (ORDER BY id) <> col2 THEN 'col2,'
WHEN LEAD(col3, 1,0) OVER (ORDER BY id) <> col3 THEN 'col3,'
WHEN LEAD(col4, 1,0) OVER (ORDER BY id) <> col4 THEN 'col4,'
) diff_cols
FROM xyz
) tmp