SQL is a declarative language, so a delimited list stored in a variable won't be evaluated. In short, I believe there are two ways of accomplishing this.

The first approach uses dynamic SQL. Build you SQL statement and then execute it. Here's an example:

declare @Var varchar(100),

@strSQL NVarchar(500);

set @Var = '''Value1'', ''Value2''';

SET @strSQL = 'SELECT * ' +

'FROM MainQuery ' +

'WHERE column1 IN (' + @Var + ');';

EXECUTE sp_executesql @strSQL;

In the other appoach you would create a temp table (let's call it #temp) and populate it with the values you want to check for. Then use normal SQL and query them using an EXISTS against the temp table. here's an example:

SELECT *

FROM MainQuery

WHERE EXISTS (SELECT 1

FROM #temp

WHERE #temp.Value = MainQuery.Column1);

Hope one of these ways works for you.