The &filter query parameter works just like the &query= parameter, and they can be used together by using the optional number (#) value. For example, if the query parameter was &query0=search_criteria, the matching filter parameter would be &filter0=additional_hidden_search_criteria. This allows the multiple weighted queries feature to work as designed while allowing administrators to add additional query details to each query.
Unlike the &query parameter, the &filter parameter can be sent multiple times. For example, if users search for software patches, you could include the various products to be searched, which could then improve search time and accuracy:
The resultant URL might appear as follows, but with the HTTP and domain name prefix:
NOTE:All &filter operators are combined by using the default &operator=value, AND. Also, the default Boolean conjunction joining the various filter operators is an OR search. You can change the default Boolean conjunction by using the &filteroperator=# query parameter. The pound sign (#) here acts just like the one used in the #operator=# query parameter.