SQL Query Group By inclusion - sql

Question

Can someone help modify the following SQL script so that I'm able to do a GROUP BY and replace the character (null).
At the moment I have two tables:
Table 1
PK_LOYALTYACCOUNT COUNTRY_ID CDC_TYPE
int varchar(50) varchar(50)
666 DE U
98 DE U
27975373 DE U
666 DE N
Table 2
PK_LOYALTYACCOUNT COUNTRY_ID CDC_TYPE
int varchar(50) varchar(50)
666 DE U
75 DE U
27975370 DE U
578 WE N
54 RT N
The results from the sql script produces the following table:
is_deleted PK_LOYALTYACCOUNT COUNTRY_ID CDC_TYPE
int int varchar(50) varchar(50)
1 666 DE U
0 666 DE U
(null) 769 DE U
(null) 578 WE N
(null) 54 RT N
However, I would like to group by the table (in any fashion) and remove or replace the null values, such that the tables appear something as follows:
COUNTRY_ID CDC_TYPE PK_LOYALTYACCOUNT is_deleted
DE U 666 1
DE U 666 0
RT N 54 replace null
WE N 578 replace null
DE N 769 replace null
The sql script is as follows:
with cmn as
( SELECT a.CDC_TYPE,
a. PK_LOYALTYACCOUNT, --Add these also in CTE result set
a.COUNTRY_ID --Add these also in CTE result set
FROM tabled a
INNER JOIN tablee b
ON a.COUNTRY_ID = b.COUNTRY_ID
AND a.PK_LOYALTYACCOUNT = b.PK_LOYALTYACCOUNT
AND a.CDC_TYPE = 'U'
)
SELECT 1 AS is_deleted,
a.*
FROM tabled a
INNER JOIN cmn
ON a.CDC_TYPE = cmn.CDC_TYPE
and a.COUNTRY_ID = cmn.COUNTRY_ID
AND a.PK_LOYALTYACCOUNT = cmn.PK_LOYALTYACCOUNT
UNION ALL
SELECT 0 AS is_deleted,
b.*
FROM tablee b
INNER JOIN cmn
ON b.CDC_TYPE = cmn.CDC_TYPE
and b.COUNTRY_ID = cmn.COUNTRY_ID
AND b.PK_LOYALTYACCOUNT = cmn.PK_LOYALTYACCOUNT
UNION ALL
SELECT NULL AS CDC_TYPE,
a.*
FROM tabled a
WHERE a.CDC_TYPE = 'N'
UNION ALL
SELECT NULL AS CDC_TYPE,
b.*
FROM tablee b
WHERE b.CDC_TYPE = 'N'
Thanks in advance

Answer 1

You could perhaps use a string for the "is_deleted" in all of those unioned queries.
But then maybe this query could also be simplified via a FULL JOIN
For example:
SELECT PK_LOYALTYACCOUNT, COUNTRY_ID, CDC_TYPE, IS_DELETED
FROM
(
SELECT
COALESCE(d.PK_LOYALTYACCOUNT, e.PK_LOYALTYACCOUNT) AS PK_LOYALTYACCOUNT,
COALESCE(d.COUNTRY_ID, e.COUNTRY_ID) AS COUNTRY_ID,
COALESCE(d.CDC_TYPE, e.CDC_TYPE) AS CDC_TYPE,
(CASE
WHEN d.CDC_TYPE = e.CDC_TYPE AND d.CDC_TYPE = 'U' THEN '1'
WHEN d.CDC_TYPE = e.CDC_TYPE AND d.CDC_TYPE = 'N' THEN '0'
ELSE ''
END) AS IS_DELETED
FROM tabled d
FULL JOIN tablee e
ON e.PK_LOYALTYACCOUNT = d.PK_LOYALTYACCOUNT
AND e.COUNTRY_ID = d.COUNTRY_ID
AND e.CDC_TYPE = d.CDC_TYPE
WHERE d.CDC_TYPE = e.CDC_TYPE
OR d.CDC_TYPE = 'N'
OR e.CDC_TYPE = 'N'
) AS cmn
GROUP BY PK_LOYALTYACCOUNT, COUNTRY_ID, CDC_TYPE, IS_DELETED
ORDER BY IS_DELETED DESC, PK_LOYALTYACCOUNT, COUNTRY_ID, CDC_TYPE;