SQL: One 2 many rows with many rows combined into one column - sql

Question

I have four tables, namely tblProject (one record), tblTeamMembers (many records), tblProjectStatus (look-up table) and tblProjectScoresComments (many records). I'm using SQL Server 2017.
Below are the table definitions:
tblProject:
[ProjectID] [INT] IDENTITY(1,1) NOT NULL,
[ProjectName] [NVARCHAR](150) NOT NULL,
[CommunityProblem] [NTEXT] NOT NULL,
[IctSolveCommunityProblem] [NTEXT] NOT NULL,
[TeamMemberRoles] [NTEXT] NOT NULL,
[ProjectImpact] [NTEXT] NOT NULL,
[HelpRaiseFunds] [NTEXT] NOT NULL,
[ProjectStatus] [INT] NOT NULL,
[CaptureDate] [DATE] NOT NULL
tblTeamMembers:
[MemberID] [INT] IDENTITY(1,1) NOT NULL,
[Person] [NVARCHAR](150) NOT NULL,
[SalRef] [NVARCHAR](50) NOT NULL,
[Email] [NVARCHAR](150) NOT NULL,
[UserName] [NVARCHAR](150) NOT NULL,
[TeamLeader] [INT] NOT NULL,
[ProjectLeader] [INT] NOT NULL,
[ProjectLeaderContactNo] [NVARCHAR](150) NULL,
[ProjectID] [INT] NOT NULL
tblProjectScoresComments
[RecID] [INT] IDENTITY(1,1) NOT NULL,
[ProjectID] [INT] NOT NULL,
[Score] [FLOAT] NOT NULL,
[Comments] [NVARCHAR](MAX) NULL,
[UserID] [NVARCHAR](150) NOT NULL,
[DateCaptured] [DATETIME] NOT NULL
tblProjectStatus:
[ProjectStatusID] [INT] IDENTITY(1,1) NOT NULL,
[ProjectStatus] [NVARCHAR](100) NOT NULL
I would like the results to return columns from all three tables, but the 3rd table (tblProjectScoresComments) has many records and for the column [Score] an average should be returned, and the [Comments] column should have all comments returned as 1 column and every comment should be separated by a comma (,).
I would like to use a query similar to the below:
SELECT
p.ProjectID, p.ProjectName AS Project,
ps.ProjectStatus,
tm.Person AS ProjectLeader,
p.CaptureDate, [AVERAGE_SCORE_FOR_ALL] AS Score,
[ALL_COMMENTS_MERGED_TO_ONE_COLUMN] AS Comments
FROM
dbo.tblProject AS p
INNER JOIN
dbo.tblProjectStatus AS ps ON p.ProjectStatus = ps.ProjectStatusID
INNER JOIN
dbo.tblTeamMembers AS tm ON p.ProjectID = tm.ProjectID
INNER JOIN
dbo.tblProjectScoresComments AS psc ON p.ProjectID = psc.ProjectID
WHERE
(tm.ProjectLeader = 1)
Results should look something like this:
ProjectID | Project | ProjectStatus | ProjectLeader | CaptureDate | Score |Comments
---------------------------------------------------------------------------------------------------------------------------------------------------------------
1 | Access to ICT-Makatane High School and Community Project | Not yet decided | Mary Ndlovu | 2019-10-04 | 1.67 |Comment 1,Comment 2,Comment 3
2 | Asample project | Rejected | Joe Soap | 2019-11-07 | 3 |Comment 1,Comment 2
Would really appreciate assistance!

Answer 1

This sounds like aggregation:
SELECT p.ProjectID, p.ProjectName AS Project, ps.ProjectStatus, tm.Person AS ProjectLeader,
p.CaptureDate,
avg(psc.score) AS avg_score,
string_agg(psc.comments, ' ') as Comments
FROM dbo.tblProject p JOIN
dbo.tblProjectStatus ps
ON p.ProjectStatus = ps.ProjectStatusID JOIN
dbo.tblTeamMembers tm
ON p.ProjectID = tm.ProjectID JOIN
dbo.tblProjectScoresComments
psc
ON p.ProjectID = psc.ProjectID
WHERE tm.ProjectLeader = 1
GROUP BY p.ProjectID, p.ProjectName AS Project, ps.ProjectStatus, tm.Person AS ProjectLeader,
p.CaptureDate;
EDIT:
The alternative to string_agg() is rather messy:
SELECT . . .,
psc.avg_score, c.comments,
FROM dbo.tblProject p JOIN
dbo.tblProjectStatus ps
ON p.ProjectStatus = ps.ProjectStatusID JOIN
dbo.tblTeamMembers tm
ON p.ProjectID = tm.ProjectID OUTER APPLY
(SELECT STUFF( (SELECT ', ' + psc.comment
FROM dbo.tblProjectScoresComments psc
WHERE p.ProjectID = psc.ProjectID
FOR XML PATH (''), TYPE
).value(N'.[1]', N'nvarchar(max)'
), 1, 2, ''
) as comments
) c OUTER APPLY
(SELECT AVG(psc.score) as avg_score
FROM dbo.tblProjectScoresComments psc
WHERE p.ProjectID = psc.ProjectID
) psc
An outer GROUP BY should not be necessary.