SQL Table data compare - sql

Question

I need to compare the two tables rows and also only show the coulmns having different data i.e mismatch data from both the table.Suppose Table1 and Table2 having 50 Columns and in that only mistach records are 5 then that coulms needs into Select statement.
Comparsion part is completed with Union query, My hurdle is how to come up with mismacted row columns names.

Answer 1

One way to do this is to have a list of all such column names concatenated in one string as:
select
T1.id, case when t1.col1<> t2.col1 then 'Col1;' else '' end +
case when t1.col2<> t2.col2 then 'Col2;' else '' end
-- similar case statementes for all th columns you want to be included
-- in the list
as Mismatchedcolumns
from Table1 T1
Join Table2 T2 on T1.id = T2.id
Check Demo here..

Answer 2

If you are looking at a list of all mismatched columns, then see below example
CREATE TABLE TableA
([Product] varchar(1), [Qty] int, [Price] int, [Comments] varchar(3))
;
INSERT INTO TableA
([Product], [Qty], [Price], [Comments])
VALUES
('A', 20, 500, 'xyz'),
('B', 50, 200, 'xyz'),
('C', 90, 100, 'abc'),
('D', 50, 500, 'xyz')
;
CREATE TABLE TableB
([Product] varchar(1), [Qty] int, [Price] int, [Comments] varchar(3))
;
INSERT INTO TableB
([Product], [Qty], [Price], [Comments])
VALUES
('B', 70, 200, 'cv'),
('C', 90, 200, 'wsd'),
('D', 40, 400, 'xyz'),
('E', 50, 500, 'xyz')
;
SELECT b.Product,
b.Qty,
b.Price,
Result = CASE WHEN a.product IS NULL THEN 'New'
ELSE 'Updated: ' +
STUFF( CASE WHEN a.Qty != b.Qty THEN ',Qty' ELSE '' END +
CASE WHEN a.Price != b.Price THEN ',Price' ELSE '' END,
1, 1, '')
END
FROM TableB b
LEFT JOIN TableA a
ON a.Product = b.Product
WHERE a.Product IS NULL
OR a.Qty != b.Qty
OR a.Price != b.Price
union
SELECT
a.Product,a.Qty,a.Price, 'NewA' as Result
FROM
TABLEA a left join
TABLEB b on a.Product = b.Product
WHERE b.Product is null
Modified version of solution at SQL Server 2008 compare two tables in same database and get column is changed
http://sqlfiddle.com/#!3/d1b3f/3