Select only one of each id sql server - sql

Question

I know this has been asked a million times before but due to the joins i am finding it hard to correctly write the code required
My SQL is
SELECT DISTINCT
newFvItems.Id, outerFvia.[UserRoleId], outerFvia.[DefaultStatusId], outerFvia.[CanBeAllocated], outerFvia.[CanCreate], outerFvia.[CanUpdate], outerFvia.[CanDelete], outerFvia.[CanSeeDraft], outerFvia.[CanSeeChecking], outerFvia.[CanSeeCompleted], outerFvia.[CanDispute], outerFvia.[CanResolveDispute], outerFvia.[CanAudit], 1, GETUTCDATE(), 393, GETUTCDATE(), 393, 0, outerFvia.[RecycleBinId], outerFvia.[FlowAccessId]
FROM FlowVersionItemAccess outerFvia
JOIN FlowVersionItems outerFvi ON outerFvi.Id = outerFvia.FlowVersionItemId
JOIN FlowVersions outerFv ON outerFv.Id = outerFvi.FlowVersionId
JOIN FlowVersionItems newFvItems ON newFvItems.FlowVersionId = 143
WHERE outerFv.Id = 133
AND outerFvia.Deleted = 0 AND outerFvi.Deleted = 0 AND outerFv.Deleted = 0
My desired output is 21 Rows, i get 27 if i remove DISTINCT i get 63
Sample data:
ID
UserId
val
val
val
val
val
val
val
val
val
val
val
val
DateTime
val
DateTime
val
val
val
val
315
2
2
0
1
1
1
1
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
7
315
6
2
0
1
1
1
1
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
12
315
7
2
0
0
0
0
0
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
16
315
7
2
0
1
1
0
0
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
16
315
18
2
0
0
0
0
0
0
0
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
69
315
18
2
0
1
1
0
0
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
69
Expected data:
ID
UserId
val
val
val
val
val
val
val
val
val
val
val
val
DateTime
val
DateTime
val
val
val
val
315
2
2
0
1
1
1
1
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
7
315
6
2
0
1
1
1
1
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
12
315
7
2
0
1
1
0
0
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
16
315
18
2
0
1
1
0
0
0
1
0
0
0
1
12/12/2022 16:53
393
12/12/2022 16:53
393
0
NULL
69
You can see UserRoleId 7 and 18 are duplicated. I tried to simply group by UserRoleId but i get errors on FlowVersionItems.Id
Msg 8120, Level 16, State 1, Line 44
Column 'FlowVersionItems.Id' is
invalid in the select list because it is not contained in either an
aggregate function or the GROUP BY clause.

Answer 1

Remove DISTINCT, add GROUP BY newFvItems.Id at the very end of query and define aggregating functions (MIN, MAX,...) for all columns you return.
DISTINCT finds all unique combinations of all columns, while you need just one column.
Alternatively, leave only DISTINCT newFvItems.Id in the select part - depends on what you actually need.

Answer 2

There are two solid approaches to this and i thought i would post my solution that i ended up using to hopefully help someone else. The group by solution is good and does provide the correct answer too but this fits an edge case better.
SELECT
newFvItems.Id,
outerFvia.[Id],
outerFvia.[UserRoleId],
outerFvia.[DefaultStatusId],
outerFvia.[CanBeAllocated],
outerFvia.[CanCreate],
outerFvia.[CanUpdate],
outerFvia.[CanDelete],
outerFvia.[CanSeeDraft],
outerFvia.[CanSeeChecking],
outerFvia.[CanSeeCompleted],
outerFvia.[CanDispute], outerFvia.[CanResolveDispute], outerFvia.[CanAudit], 1, GETUTCDATE(), 393, GETUTCDATE(), 393, 0, outerFvia.[RecycleBinId], outerFvia.[FlowAccessId]
FROM FlowVersionItemAccess outerFvia
INNER JOIN FlowVersionItems outerFvi ON outerFvi.Id = outerFvia.FlowVersionItemId
AND outerFvi.Deleted = 0
INNER JOIN FlowVersions outerFv ON outerFv.Id = outerFvi.FlowVersionId
AND outerFv.Deleted = 0
INNER JOIN FlowVersionItems newFvItems ON newFvItems.FlowVersionId = 143
AND newFvItems.Deleted = 0
AND newFvItems.[Order] = outerFvi.[Order]
WHERE outerFvia.Deleted = 0
AND outerFv.Id = 133
Here is the group by solution too.
SELECT
newFvItems.Id,
outerFvia.[UserRoleId],
MAX(outerFvia.[DefaultStatusId]),
MAX(CAST(outerFvia.[CanBeAllocated] As tinyint)),
MAX(CAST(outerFvia.[CanCreate] as tinyint)),
MAX(CAST(outerFvia.[CanUpdate] as tinyint)),
MAX(CAST(outerFvia.[CanDelete] as tinyint)),
MAX(CAST(outerFvia.[CanSeeDraft] as tinyint)),
MAX(CAST(outerFvia.[CanSeeChecking] as tinyint)),
MAX(CAST(outerFvia.[CanSeeCompleted] as tinyint)),
MAX(CAST(outerFvia.[CanDispute] as tinyint))
--, MAX(outerFvia.[CanResolveDispute]), MAX(outerFvia.[CanAudit]), 1, GETUTCDATE(), 393, GETUTCDATE(), 393, 0, MAX(outerFvia.[RecycleBinId]), MAX(outerFvia.[FlowAccessId])
FROM FlowVersionItemAccess outerFvia
JOIN FlowVersionItems outerFvi ON outerFvi.Id = outerFvia.FlowVersionItemId
JOIN FlowVersions outerFv ON outerFv.Id = outerFvi.FlowVersionId
JOIN FlowVersionItems newFvItems ON newFvItems.FlowVersionId = 143
WHERE outerFv.Id = 133
AND outerFvia.Deleted = 0 AND outerFvi.Deleted = 0 AND outerFv.Deleted = 0 AND newFvItems.Deleted = 0
group by newFvItems.Id, outerFvia.[UserRoleId]
Hopefully me posting the solutions i came up with helps someone else, i know this question gets asked a lot and if it wasn't for the joins it would be a lot easier.