SUM a column count from two tables - sql

Question

I have this simple unioned query in SQL Server 2014 where I am getting counts of rows from each table, and then trying to add a TOTAL row at the bottom that will SUM the counts from both tables. I believe the problem is the LEFT OUTER JOIN on the last union seems to be only summing the totals from the first table
SELECT A.TEST_CODE, B.DIVISION, COUNT(*)
FROM ALL_USERS B, SIGMA_TEST A
WHERE B.DOMID = A.DOMID
GROUP BY A.TEST_CODE, B.DIVISION
UNION
SELECT E.TEST_CODE, F.DIVISION, COUNT(*)
FROM BETA_TEST E, ALL_USERS F
WHERE E.DOMID = F.DOMID
GROUP BY E.TEST_CODE, F.DIVISION
UNION
SELECT 'TOTAL', '', COUNT(*)
FROM (SIGMA_TEST A LEFT OUTER JOIN BETA_TEST E ON A.DOMID
= E.DOMID )
Here is a sample of the results I am getting:
I would expect the TOTAL row to display a result of 6 (2+1+3=6)
I would like to avoid using a Common Table Expression (CTE) if possible. Thanks in advance!

Answer 1

Since you are counting users with matching DOMIDs in the first two statements, the final statement also needs to include the ALL_USERS table. The final statement should be:
SELECT 'TOTAL', '', COUNT(*)
FROM ALL_USERS G LEFT OUTER JOIN
SIGMA_TEST H ON G.DOMID = H.DOMID
LEFT OUTER JOIN BETA_TEST I ON I.DOMID = G.DOMID
WHERE (H.TEST_CODE IS NOT NULL OR I.TEST_CODE IS NOT NULL)

Answer 2

I would consider doing a UNION ALL first then COUNT:
SELECT COALESCE(TEST_CODE, 'TOTAL'),
DIVISION,
COUNT(*)
FROM (
SELECT A.TEST_CODE, B.DIVISION
FROM ALL_USERS B
INNER JOIN SIGMA_TEST A ON B.DOMID = A.DOMID
UNION ALL
SELECT E.TEST_CODE, F.DIVISION
FROM BETA_TEST E
INNER JOIN ALL_USERS F ON E.DOMID = F.DOMID ) AS T
GROUP BY GROUPING SETS ((TEST_CODE, DIVISION ), ())
Using GROUPING SETS you can easily get the total, so there is no need to add a third subquery.
Note: I assume you want just one count per (TEST_CODE, DIVISION). Otherwise you have to also group on the source table as well, as in #Gareth's answer.

Answer 3

I think you can achieve this with a single query. It seems your test tables have similar structures, so you can union them together and join to ALL_USERS, finally, you can use GROUPING SETS to get the total
SELECT ISNULL(T.TEST_CODE, 'TOTAL') AS TEST_CODE,
ISNULL(U.DIVISION, '') AS DIVISION,
COUNT(*)
FROM ALL_USERS AS U
INNER JOIN
( SELECT DOMID, TEST_CODE, 'SIGNMA' AS SOURCETABLE
FROM SIGMA_TEST
UNION ALL
SELECT DOMID, TEST_CODE, 'BETA' AS SOURCETABLE
FROM BETA_TEST
) AS T
ON T.DOMID = U.DOMID
GROUP BY GROUPING SETS ((T.TEST_CODE, U.DIVISION, T.SOURCETABLE), ());
As an aside, the implicit join syntax you are using was replaced over a quarter of a century ago in ANSI 92. It is not wrong, but there seems to be little reason to continue to use it, especially when you are mixing and matching with explicit outer joins and implicit inner joins. Anyone else that might read your SQL will certainly appreciate consistency.