Sum on columns with the same ID and different columns? - sql

Question

Using Microsoft SQL Server
I need to create a table that takes the User IDs from the temp table. Collects only those User IDs and then adds all of the Points for that individual user together.
Temp table which pulled all the most recent records for each User ID.
User ID | Points | Date Field
-----------------------------
1 1 10/31/2016
3 1 08/26/2016
Main
User ID | Points | Date Field | Other Field
--------------------------------------------
1 1 10/31/2016 N/A
1 2 10/25/2016 N/A
1 3 09/18/2016 N/A
2 1 08/17/2017 N/A
2 16 07/11/2017 N/A
3 1 08/27/2016 N/A
3 5 05/14/2016 N/A
So take temp table and match those User IDs to the main table. From that data you should only have collected those which match the record IDs in the temp table. From there the report will then be broken down to look like below. Which shows the most recent date, and a sum of all the points for that User ID.
User ID | Points | Date Field | Other Field
---------------------------------------------
1 6 10/31/2016 N/A
3 6 08/27/2016 N/A
I tried this SQL:
SELECT
a.[User ID], a.[Points], a.[Date Field], a.[Other Field1], a.[Other Field2], a.[Other Field3],
(CASE WHEN b.[User ID] = a.[User ID] THEN SUM(a.Points) END) AS [Total Points]
FROM
Main_Table a
INNER JOIN
#Temp b ON b.[User ID] = a.[User ID]
GROUP BY
a.[User ID], [Points], [Date Field], [Other Field1], [Other Field2], [Other Field3]
I get the total points column, but is not adding all the fields with identical User IDs together.
I just need to know where I am going wrong. I'm not the best with SQL and I'm still learning. Please understand I am trying my best to figure this out.
Thank you!

Answer 1

I imagine something like this is what you're looking for:
SELECT
b.[User ID]
, b.[Points]
, b.[Date Field]
, SUM(a.Points) [Total Points]
FROM
#Temp b
INNER JOIN Main_Table a ON b.[User ID] = a.[User ID]
GROUP BY
b.[User ID]
, b.[Points]
, b.[Date Field]
But then the question would be, which of the other fields from Main_Table do you want to keep?
I imagine possibly something like this:
SELECT
b.[User ID]
, b.[Points]
, b.[Date Field]
, m.[Other_Field] -- etc.
, SUM(a.Points) [Total Points]
FROM
#Temp b
INNER JOIN Main_Table m ON
b.[User ID] = m.[User ID]
AND b.[Date Field] = m.[Date Field]
INNER JOIN Main_Table a ON b.[User ID] = a.[User ID]
GROUP BY
b.[User ID]
, b.[Points]
, b.[Date Field]
, m.[Other_Field]

Answer 2

To get Sum, you have to group by fields that are non-changing. So User ID is the non-changing field you would want to SUM by. The group by is done to this non-aggregate field User ID. The problem with date and [Other Field] is that they are changing often. This defeats the group by. You have to query back to the original table to get the max date field if that's your intent. I'm not sure what [Other Field] are, but you have to take into account if they are different changing values.
SELECT dT.[User ID]
,dT.Points
,(SELECT MAX([Date Field])
FROM #main M2
WHERE M2.[User ID] = dT.[User ID]) AS [Date Field]
FROM (
SELECT M.[User ID]
,SUM(M.Points) AS Points
FROM #main M
WHERE [User ID] IN (SELECT [User ID] FROM #temp)
GROUP BY M.[User ID]
) AS dT
Creates output:
User ID Points Date Field
1 6 2016-10-31
3 6 2016-08-27

Answer 3

I assume this should help
--======================= CREATE TEMP TABLE==============================
CREATE TABLE #TEMP ([USER ID] INT,
POINTS INT,
[DATE FIELD] DATE)
--======================= VALUES ON THE TABLE ===============================
INSERT INTO #TEMP VALUES ( 1 ,1,'10-31-2016')
INSERT INTO #TEMP VALUES (3,1,'08-26-2016')
--======================== CREATE MAIN TABLE ============================
CREATE TABLE #MAIN ([USER ID] INT,
POINTS INT,
[DATE FIELD] DATE,
[OTHER FIELD] NVARCHAR(50))
--======================= VALUES ON MAIN TABLE===================
INSERT INTO #MAIN VALUES ( 1,1,'10-31-2016','N/A')
INSERT INTO #MAIN VALUES ( 1,2,'10-25-2016','N/A')
INSERT INTO #MAIN VALUES ( 1,3,'09-18-2016','N/A')
INSERT INTO #MAIN VALUES ( 2,1,'08-17-2017','N/A')
INSERT INTO #MAIN VALUES ( 2,16,'07-11-2017','N/A')
INSERT INTO #MAIN VALUES ( 3,1,'08-27-2016','N/A')
INSERT INTO #MAIN VALUES ( 3,5,'05-14-2016','N/A')
--=====GETTING SUM OF YOUR POINTS=====
SELECT T2.[USER ID],
SUM(T1.[POINTS]) AS [TOTAL POINT],
T2.[DATE FIELD],
T1.[OTHER FIELD]
FROM #MAIN AS T1
RIGHT JOIN #TEMP AS T2
ON T1.[USER ID] = T2.[USER ID]
GROUP BY T2.[USER ID],
T2.[DATE FIELD],
T1.[OTHER FIELD]
DROP TABLE #TEMP
DROP TABLE #MAIN