I think u should first join all the tables so that all the fields that need to be filtered is in one single table. Then its easy to apply those filters.
Qlikview will not let u filter data referring to other tables that have been loaded before(in the scripting part).
If u want to keep them in different tables, u can find a key column that will link all the three table and u can filter out data while showing it in the Front end with Calculated dimension and Set analysis. But this is going to reduce the performance and the calculations would become complex and heavy.
If u r going to have data as u have posted, then it is best to filter the data at script level by using all the filters in the same table. As u have all the Fields in the same table. Then while loading the rest 2 tables u can use where exists to filter out the data. If u r about to filter data with a field in other tables then u will have to join them.
say u have closegroup sales in closer table and u wan to filter data according to that also, u will have to join the tables to achieve it.
actually, case table with not "owner workgroup" & "closer workgroup" field, need use "owner table id" & "closer table id" to joins the owner table and closer table.
for case table, there are more then 1 million cases every month; for owner table & closer table, there are more than 50 thousands account.
as results, in fact only very few cases, maybe 4 or 5 cases.
base on the background:
i can't filter case table with "owner workgroup","closer workgroup" and "open date", because there are not "owner workgroup" &"closer workgroup" field. if only filter "open date", for case table should be load more than hundreds of thousands cases. for only a few cases results, the amount of load data is too large.
So, i am looking for a better solution, more quickly and with less data.