Linked servers will be the easiest way. Then you just add the server name as a prefix:

SELECT *
  FROM [ServerName].[DatabaseName].[SchemaName].[TableName]

https://docs.microsoft.com/en-us/sql/relational-databases/linked-servers/linked-servers-database-engine?view=sql-server-ver15

These are your subqueries

           ,(SELECT RS.LIB_SERVICE 
          ...

One of the major ideas of client/server architecture was that the system would come in tiers. The database layer would get a result set, then pass that set on...

If you want the SQL optimised you would be better off giving us the actual SQL that is generated along with the execution plan.

The optimiser should make them have the...

Set up the data:

if object_id('tempdb..#a','U') is not null
    drop table #a

if object_id('tempdb..#b','U') is not null
    drop table #b
go

create table #a 
(
...

I know it's a temporary...

Your database is not normalised.

The standard way to store this is to have two tables instead of your #u table

CREATE TABLE #User
(
    UserID int...

I need to count the number of times each surgeon has done a procedure where op1 to op4 includes procedure b AND d OR just d irrespective of any...

Or you could...

I've  put an LTRIM on the output to make it the same as the SQL Server version, also it was searching the string for the delimiter one short of the...

Great, thank you for the correction. Here is another Problem to consider

INSERT INTO @Test SELECT value FROM dbo.STRING_SPLIT('Abc, Ced, Def, ', ', ')

gives "Abc", "Ced" and "Def,...

Is this what you want?

SELECT a.Eid , b.typ
  FROM sample_data a
 CROSS JOIN sample_data b
 ORDER BY 1, 2

So you are just trying to make sure you don't load the same file twice. Maybe if you create another table of all the files you have loaded, insert a...

Why are you worried about getting duplicates?

If you make sure the same file isn't loaded twice then would that solve your problem?