SQL - Comma Delimited subset results of multiple column in its own column - sql-server

Question

I have a view with a union all table, a person may belong to one or many table.
how do i create a query that will add a column with a ';' delimited where the person belong to, the ID is unique per person.
here's the example
--table1
PID fName tableMem
1 test group1
2 test2 group1
--table2
PID fName tableMem
1 test group2
3 test3 group2
--table3
PID fName tableMem
1 test group3
3 test3 group3
Here's the output I wanted
--compiled table after union of all the 3 tables
PID fname tableMem
1 test group1;group2;group3
2 test2 group1
3 test3 group2;group3
Here's the query I built from reading here for the past 2 days.I'm using STUFF and partition because I need the row to be distinct and this query will run as view.
SELECT *
FROM
(SELECT
*,
ROW_NUMBER() OVER(PARTITION BY PIP ORDER BY Fname) AS rownum
FROM
(SELECT
*,
STUFF((SELECT ';'+ di.tablemem
FROM DPI di <<-- alias table from union
WHERE DPI.PID = di.PID
FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, '') tablemem
FROM
(SELECT *
FROM
(--table1
SELECT 'group1' AS tableMem, * FROM table1
UNION ALL
--table2
SELECT 'group2' AS tableMem, * FROM table2
UNION ALL
--table3
SELECT 'group3' AS tableMem, * FROM table3) AS DPI <<--alias table name
) AS innertable
) AS distinctTable
) AS outerTable
WHERE
rownum = 1
what am I missing or what is wrong with the query. I'm guessing its because Im using a derived table name of the union sub select. is there any workaround?
Thank you in advance

Answer 1

You need GROUP BY data by PID, fName, using the FOR XML aggregation it would be
WITH DPI AS (
--table1
Select 'group1' as tableMem,* from table1
UNION ALL
--table2
Select 'group2' as tableMem,* from table2
UNION ALL
--table3
Select 'group3' as tableMem,* from table3
)
SELECT PID, fName
, STUFF((
SELECT ';'+ di.tablemem
FROM DPI di
WHERE di.PID = di1.PID
FOR XML PATH(''),TYPE).value('.','NVARCHAR(MAX)'),1,1,'') tablemem
FROM DPI di1
GROUP BY PID, fName;

Answer 2

Here is a possible solution using CTE:
;with cte as (
select * from #tbl1
union all
select * from #tbl2
union all
select * from #tbl3
)
select distinct
pid
,fname
,stuff(
(select '; ' + tableMem
from cte
where pid = a.pid
and fname = a.fname
FOR XML PATH(''),TYPE)
.value('text()[1]','nvarchar(max)'),1,2,N'') as tableMem
from cte a

Answer 3

Given that you have a finite number of tables, I think I find this simpler:
select p.pid, p.fname,
trim(';' from
(case when t1.pid is not null then 'group1;' else '' end) +
(case when t2.pid is not null then 'group2;' else '' end) +
(case when t3.pid is not null then 'group3;' else '' end)
) as groups
from (select pid, fname from table1 union -- on purpose to remove duplicates
select pid, fname from table2 union
select pid, fname from table3
) p left join
table1 t1
on t1.pid = p.pid left join
table2 t2
on t2.pid = p.pid left join
table3 t3
on t3.pid = p.pid;
The most recent version of SQL Server supports string_agg(), which would make this simpler still.

Answer 4

Try this:
DECLARE #table1 TABLE
(
[PID] TINYINT
,[fname] VARCHAR(12)
,[tableMem] VARCHAR(12)
);
DECLARE #table2 TABLE
(
[PID] TINYINT
,[fname] VARCHAR(12)
,[tableMem] VARCHAR(12)
);
DECLARE #table3 TABLE
(
[PID] TINYINT
,[fname] VARCHAR(12)
,[tableMem] VARCHAR(12)
);
INSERT INTO #table1 ([PID], [fname], [tableMem])
VALUES (1, 'test', 'group1')
,(2, 'test2', 'group1');
INSERT INTO #table2 ([PID], [fname], [tableMem])
VALUES (1, 'test', 'group2')
,(3, 'test3 ', 'group2');
INSERT INTO #table3 ([PID], [fname], [tableMem])
VALUES (1, 'test', 'group3')
,(3, 'test3 ', 'group3');
WITH DataSource AS
(
SELECT *
FROM #table1
UNION ALL
SELECT *
FROM #table2
UNION ALL
SELECT *
FROM #table3
)
SELECT DISTINCT DS.[PID]
,DS.fname
,CSVvalue.[tableMem]
FROM DataSource DS
CROSS APPLY
(
SELECT STUFF
(
(
SELECT ',' + DS1.[tableMem]
FROM DataSource DS1
WHERE DS.[PID] = DS1.[PID]
AND DS.[fname] = DS1.[fname]
ORDER BY DS1.[tableMem]
FOR XML PATH(''), TYPE
).value('.', 'VARCHAR(MAX)')
,1
,1
,''
)
) CSVvalue ([tableMem]);