SUM On Column With Group By SQL - sql-server

Question

I have following data:
+----------------+--------------+-----+
| StgDescription | ID | Amt |
+----------------+--------------+-----+
| A | OA17 | 11 |
| A | OA17 | 11 |
| A | OA17 | 11 |
| A | OA17 | 11 |
| B | ZA47/ A | 12 |
| B | ZA47/ A | 12 |
| B | ZA47/ B | 10 |
| B | ZA47/ B | 10 |
| B | ZA48/ A | 14 |
| B | ZA48/ F | 10 |
| B | ZA48 /G | 13 |
| B | ZA48 /H | 10 |
| B | ZA48/ I | 15 |
| B | ZA48/ J | 10 |
| B | ZA48/ K | 16 |
| B | ZA48/ L | 10 |
| c | FA01LM100340 | 10 |
| c | PA53 AE | 10 |
+----------------+--------------+-----+
I want to generate report in following format. The amount should be sum for ID for same StgDescription.
+----------------+-----+
| StgDescription | Amt |
+----------------+-----+
| a | 11 |
| b | 120 |
| c | 20 |
+----------------+-----+
I've written following query to get this result:
WITH CTE AS(
SELECT
distinct
s.StgDescription
,p.ID
,Amt
FROM [DinDb].[dbo].[tblTvlTransaction] t
JOIN tblstgmaster s on t.StgId=s.StgId
JOIN tblProjDocSt p on t.TDocID=p.DocId
JOIN [PdasDb].[dbo].[tblIDmaster] f ON p.ID=f.ID
where OptAuthoDateTime between '2015-07-27 00:00:00' and '2015-09-01 00:00:00')
select StgDescription,sum(AMT) from cte group by StgDescription
Is there any other efficient alternative to do this?

Answer 1

First in cte remove duplicates, then GROUP BY like:
WITH cte AS (
SELECT DISTINCT StgDescription, ID, Amt
FROM your_tab
)
SELECT
StgDescription,
Amt = SUM(Amt)
FROM cte
GROUP BY StgDescription;
OR:
WITH cte AS (
SELECT StgDescription, ID, Amt
FROM your_tab
GROUP BY StgDescription, ID, Amt
)
SELECT
StgDescription,
Amt = SUM(Amt)
FROM cte
GROUP BY StgDescription;

Answer 2

I hope that you get the data from a query, not from a table. It would not be good to store data thus redundantly. And it would not be gould to name a column ID which is not the unique identifier for a row in a table.
Your problem with the data is that you have duplicates, which prevents you from getting the sum directly. So use DISTINCT to make your data unique first.
If this data is from a query then simply add DISTINCT after the SELECT keyword. If not, use a derived table (i.e. a subquery) where you select distinct records from the table.
select stgdescription, sum(amt)
from
(
select distinct stgdescription, id, amt
from mydata
) distinct_data
group by stgdescription;
You may want to replace stgdescription with lower(stgdescription), though, if stgdescription can be 'A' or 'a' and you want to treat them the same.

Answer 3

I'd keep it as simple as possible, like this:
select StgDescription, sum(Amt) from
(
select distinct StgDescription, ID, Amt from tablename
) a
group by StgDescription
Hope it helps!

Answer 4

I suspect your duplicates are coming from [tblTvlTransaction], therefore, I would remove this table as a JOIN and use EXISTS to just check a record is there. So essentially the only tables in the FROM clause are those you actually need data from:
SELECT s.StgDescription, p.ID, s.Amt
FROM tblstgmaster AS s
INNER JOIN tblProjDocSt p on
t.TDocID = p.DocId
INNER JOIN [PdasDb].[dbo].[tblIDmaster] AS f
ON p.ID = f.ID
WHERE EXISTS
( SELECT 1
FROM [DinDb].[dbo].[tblTvlTransaction] AS t
WHERE t.OptAuthoDateTime BETWEEN '2015-07-27 00:00:00' AND '2015-09-01 00:00:00'
AND t.StgId = s.StgId
);
The advantage of EXISTS is that it can use a semi-join, which essentially means rather than pulling back all the rows from the transaction table, it will stop the seek/scan as soon as it finds one matching record. This should leave you without duplicates so you can do the SUM directly:
SELECT s.StgDescription, Amount = SUM(s.Amt)
FROM tblstgmaster AS s
INNER JOIN tblProjDocSt p on
t.TDocID = p.DocId
INNER JOIN [PdasDb].[dbo].[tblIDmaster] AS f
ON p.ID = f.ID
WHERE EXISTS
( SELECT 1
FROM [DinDb].[dbo].[tblTvlTransaction] AS t
WHERE t.OptAuthoDateTime BETWEEN '2015-07-27 00:00:00' AND '2015-09-01 00:00:00'
AND t.StgId = s.StgId
)
GROUP BY s.StgDescription;