Trying to set like that will not work.

e.g. Set @ClientID in (...)

Where is the source of this data?

If it is coming from a database, you can use a select instead of the values method.

If this is coming from an app (via delimited fashion maybe), then a loop would work with the values method you have there.

It is also possible to dump the values for clientid into a temp table and then use the select statement for the insert instead.

Make sense?