i need to fetch a list of IDs from a table based on a filter is there a way i can do that without having to fetch all other entities data i need to send that list to a client where he already has this data on his machine

You could use a dynamic list for this, by just fetching that single field into a datatable, or you could use the ResultsetFields used to fetch the dynamic list also to fetch a projection and project it onto the entity class, which gives entity instances with just the ID filled .