One method would be a string splitter.

Take a look in my signature for Jeff's string splitter and call it in your query

declare @temp table(Userid int, forename varchar(200), surname varchar(200), locationid int)

insert into @temp values (1,'ant','green',1),(2,'green','ant',2)

declare @param varchar(10) = '1,2'

SELECT

UserID,

Forename,

Surname

FROM

@temp t

INNER JOIN

dbo.DelimitedSplit8K(@param,',') f

on

t.locationid = f.Item