SQL Server mulitple results to one row by ID (Version 2012) - sql

Question

Consider this query and result set:
Select udbA.userId, d.dbName
from user_db_access udbA
Inner join dbList d on d.dbid = udbA.dbid
Order By udbA.userId
1 az
1 nc_west
1 bsc_mo
1 NS_002
What I am looking for is a way to flatten this into one record. I know I can do it with a temp table and select into, but I was curious to see if a query could do it directly. A user could have up to 15 databases available to them.
Looking for results like below ( 2 columns -- userid and the database names ):
userid dbname
1 az nc_west bsc_mo NS_002
SQL Server Version: Microsoft SQL Server 2012 (SP3) (KB3072779) - 11.0.6020.0 (X64) Oct 20 2015 15:36:27 Copyright (c) Microsoft Corporation Enterprise Edition (64-bit) on Windows NT 6.3 (Build 9600: ) (Hypervisor)

Answer 1

Assuming you want a space-delimited list of database names:
DECLARE #Access table ( userId int, dbName varchar(50) );
INSERT INTO #Access VALUES
( 1, 'az' ), ( 1, 'nc_west' ), ( 1, 'bsc_mo' ), ( 1, 'NS_002' );
SELECT DISTINCT
ax.userId, db.list
FROM #Access AS ax
OUTER APPLY (
SELECT LTRIM ( (
SELECT ' ' + dbName AS "text()" FROM #Access AS x WHERE x.userId = ax.userId
FOR XML PATH ( '' )
) ) AS list
) AS db;
Returns
+--------+--------------------------+
| userId | list |
+--------+--------------------------+
| 1 | az nc_west bsc_mo NS_002 |
+--------+--------------------------+
For a comma-delimited list:
SELECT DISTINCT
ax.userId, db.list
FROM #Access AS ax
OUTER APPLY (
SELECT STUFF ( (
SELECT ',' + dbName AS "text()" FROM #Access AS x WHERE x.userId = ax.userId
FOR XML PATH ( '' )
), 1, 1, '' ) AS list
) AS db;
Returns
+--------+--------------------------+
| userId | list |
+--------+--------------------------+
| 1 | az,nc_west,bsc_mo,NS_002 |
+--------+--------------------------+

Answer 2

You need GROUP BY and row_number as follows:
select userId,
max(case when rn = 1 then dbName end) as val1,
max(case when rn = 2 then dbName end) as val2,
max(case when rn = 3 then dbName end) as val3,
max(case when rn = 4 then dbName end) as val4
from
(Select udbA.userId, d.dbName,
row_number() over (partition by udbA.userId order by d.dbName) as rn
from user_db_access udbA
Inner join dbList d on d.dbid = udbA.dbid ) t
group by userId
-- update
You just need two columns then use the STRING_AGG as follows:
Select udbA.userId,
string_agg(d.dbName, ' ') within group (order by d.dbName) as dbName
from user_db_access udbA
Inner join dbList d on d.dbid = udbA.dbid
group by udbA,userId
-- For SQL server 2012
Select distinct udbA.userId,
STUFF((SELECT distinct '' + d.dbName
from dbList d
where d.dbid = udbA.dbid
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,0,'') AS dbid
FROM user_db_access udbA
WHERE EXISTS (SELECT 1 FROM dbList d
where d.dbid = udbA.dbid)
Or use CTE as follows:
with CTE as
(Select udbA.userId, d.dbName
from user_db_access udbA
Inner join dbList d on d.dbid = udbA.dbid)
Select distinct c.userId,
STUFF((SELECT distinct '' + cc.dbName
from cte cc
where c.dbid = cc.dbid
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,0,'') AS dbid
FROM cte c

Answer 3

Depending on your SQL Server version you can use STRING_AGG
Like this:
Select udbA.userId, string_agg(d.dbName, ', ') as name
from user_db_access udbA
Inner join dbList d on d.dbid = udbA.dbid
group by udbA.userId
If you are using an older version you already have answers here: How to make a query with group_concat in sql server
Like this:
select
udbA.userId,
stuff((
select cast(',' as varchar(max)) + d.dbName
from dbList d
where d.dbid = udbA.dbid
order by d.dbName
for xml path('')), 1, 1, '') as dbList
from
user_db_access udbA
inner join dbList dl on dl.dbid = udbA.dbid
order by
udbA.userId;