SSRS comparison of two datasets for "Difference Table" - reporting-services

Question

We are rolling out new Symantec clients that connect to a new server. I've built a report that shows the rollout status.
So far so good. Now I try to report the servers, that are not visible in the new environment.
Source 1: SEPM-Database on SQL Server A
Source 2: SCCM-Database on SQL Server B
Datasets that querying the things that I need are already there.
Server name values of the fields are identical.
My goal is a table that compares:
"SEPM-Database servernames" with "SCCM-Database servernames"
and writes only the server names into the table that ARE NOT in both.
Need this to check out which server hasn't joined the new environment.
Sorry, hope you understand what I mean. SSRS is very new to me. In the attached screenshot, you can see my first report that I have now:
First report created
Visual overview database "relations"

Answer 1

You could do it as a full join like this.
WITH
sepm_server_list
AS
(
SELECT tbl.* FROM (VALUES
( 'SEPM', 'Server1')
, ( 'SEPM', 'Server2')
, ( 'SEPM', 'Server3')
, ( 'SEPM', 'Server4')
) tbl ([DatabaseName], [ServerName])
)
,
sccm_server_list
AS
(
SELECT tbl.* FROM (VALUES
( 'SCCM', 'Server1')
, ( 'SCCM', 'Server2')
, ( 'SCCM', 'Server3')
, ( 'SCCM', 'Server5')
) tbl ([DatabaseName], [ServerName])
)
SELECT
sepm.*
, sccm.*
FROM
sepm_server_list AS sepm
FULL JOIN sccm_server_list AS sccm ON sepm.[ServerName] = sccm.[ServerName]
WHERE
1=1
AND
(
sepm.[ServerName] IS NULL
OR
sccm.[ServerName] IS NULL
)
Or you could write it as an except statement with a union, to get the values in the same columns.
WITH
sepm_server_list
AS
(
SELECT tbl.* FROM (VALUES
( 'SEPM', 'Server1')
, ( 'SEPM', 'Server2')
, ( 'SEPM', 'Server3')
, ( 'SEPM', 'Server4')
) tbl ([DatabaseName], [ServerName])
)
,
sccm_server_list
AS
(
SELECT tbl.* FROM (VALUES
( 'SCCM', 'Server1')
, ( 'SCCM', 'Server2')
, ( 'SCCM', 'Server3')
, ( 'SCCM', 'Server5')
) tbl ([DatabaseName], [ServerName])
)
SELECT DatabaseName = 'SEPM', A.[ServerName] FROM
(
SELECT [ServerName] FROM sepm_server_list
EXCEPT
SELECT [ServerName] FROM sccm_server_list
) A
UNION
SELECT DatabaseName = 'SCCM', B.[ServerName] FROM
(
SELECT [ServerName] FROM sccm_server_list
EXCEPT
SELECT [ServerName] FROM sepm_server_list
) B
Here's an example with the queries you posted.
WITH
sepm_server_list
AS
(
SELECT [DatabaseName] = 'SEPM', [ServerName] = COMPUTER_NAME FROM v_sem_computer
)
,
sccm_server_list
AS
(
SELECT [DatabaseName] = 'SCCM', [ServerName] = F.[Name] FROM (v_Collection AS C LEFT JOIN v_FullCollectionMembership AS F ON F.CollectionID = C.CollectionID) WHERE C.[Name] = 'ALL_SERVERS_neu'
)
SELECT DatabaseName = 'SEPM', A.[ServerName] FROM
(
SELECT [ServerName] FROM sepm_server_list
EXCEPT
SELECT [ServerName] FROM sccm_server_list
) A
UNION
SELECT DatabaseName = 'SCCM', B.[ServerName] FROM
(
SELECT [ServerName] FROM sccm_server_list
EXCEPT
SELECT [ServerName] FROM sepm_server_list
) B