How to Find Rows which are Duplicates by a Key but Not Duplicates in All Columns?

Question

I am working with a table which is an extract of a set of other tables. All of the rows of the extract table should be unique according to keys D1, D2 and D3. They are not.

Answer 1

Any reason you don't just create another table expression to cover more fields and join to that one?

WITH DUPLICATEKEY(D1,D2,D3) AS
(
    SELECT D1, D2, D3
    FROM SOURCE
    GROUP BY D1, D2, D3
    HAVING COUNT(*)>1
)
WITH NODUPES(D1,D2,D3,C4,C5,C6) AS
(
SELECT 
S.D1, S.D2, S.D3, S.C4, S.C5, S.C6
FROM SOURCE S
GROUP BY
 S.D1, S.D2, S.D3, S.C4, S.C5, S.C6
HAVING COUNT(*)=1
)

SELECT S.D1, S.D2, S.D3, S.C4, S.C5, S.C6
FROM SOURCE S
INNER JOIN DUPLICATEKEY D
    ON S.D1 = D.D1 AND S.D2 = D.D2 AND S.D3 = D.D3

INNER JOIN NODUPES D2
    ON S.D1 = D2.D1 AND S.D2 = D2.D2 AND S.D3 = D2.D3

ORDER BY S.D1, S.D2, S.D3, S.C4, S.C5, S.C6