Why is GROUP BY not working in SQL Server? - sql

Question

I have the following query:
SELECT TOP 500
BusinessDate,
BRANCH_CO_MNE,
RIGHT(TRANS_INPUTTER, 5) 'USER_ID',
CASE
WHEN TRANS_TYPE LIKE '%Deposit%'
THEN COUNT(*)
END 'No of Cash Deposit'
FROM test_link.MMBL_phase2.dbo.EB_MMBL_H_UAR_PROT
WHERE BusinessDate = '2023-01-23'
GROUP BY BusinessDate,
BRANCH_CO_MNE,
TRANS_INPUTTER,
TRANS_TYPE
ORDER BY USER_ID
Which returns the following results:
BusinessDate
BRANCH_CO_MNE
USER_ID
No of Cash Deposit
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
11748
NULL
2023-01-23
BNK
11748
NULL
2023-01-23
BNK
11748
NULL
2023-01-23
BNK
11748
NULL
2023-01-23
BNK
11748
NULL
2023-01-23
BNK
11748
18
2023-01-23
BNK
11748
NULL
The NULL values are repeating while I have put the No of Cash Deposit in GROUP BY clause.
Shouldn't the results be like
BusinessDate
BRANCH_CO_MNE
USER_ID
No of Cash Deposit
2023-01-23
BNK
10938
NULL
2023-01-23
BNK
11748
18
2023-01-23
BNK
11748
NULL

Answer 1

I suspect the problem here is your attempt at conditional aggregation. For conditional aggregation the aggregation function doesn't go inside the CASE expression, the CASE expression is put inside the aggregate function. As a result of your method, you have to GROUP BY the column TRANS_INPUTTER because it's not being aggregated.
If you switch to conditional aggregation, then you can remove TRANS_TYPE from the GROUP BY. Also, you then need to change the GROUP BY on TRANS_INPUTTER to be RIGHT(TRANS_INPUTTER, 5).
SELECT TOP (500)
BusinessDate,
BRANCH_CO_MNE,
RIGHT(TRANS_INPUTTER, 5) AS USER_ID,
COUNT(CASE WHEN TRANS_TYPE LIKE '%Deposit%' THEN 1 END) AS [No of Cash Deposit]
FROM test_link.MMBL_phase2.dbo.EB_MMBL_H_UAR_PROT
WHERE BusinessDate = '2023-01-23'
GROUP BY BusinessDate,
BRANCH_CO_MNE,
RIGHT(TRANS_INPUTTER, 5)
ORDER BY USER_ID;

Answer 2

You are also grouping on TRANS_INPUTTER and TRANS_TYPE. When those values are different, you will have also rows for those even if you don't specify them in your SELECT statement.
However as we don't have scripts for testdata I cannot reproduce your problem for now.

Answer 3

SELECT TOP 500
BusinessDate,
BRANCH_CO_MNE,
RIGHT(TRANS_INPUTTER, 5) 'USER_ID',
CASE
WHEN TRANS_TYPE LIKE '%Deposit%'
THEN COUNT(*)
END 'No of Cash Deposit'
FROM test_link.MMBL_phase2.dbo.EB_MMBL_H_UAR_PROT
WHERE BusinessDate = '2023-01-23'
GROUP BY BusinessDate,
BRANCH_CO_MNE,
RIGHT(TRANS_INPUTTER, 5),
CASE
WHEN TRANS_TYPE LIKE '%Deposit%'
THEN COUNT(*)
END
ORDER BY USER_ID