Good day. I have 2 different situations where I need a dependent drop-down field. First is for a subform, where I want to show related fields for a specific customer on the main form. In my case it is a parent whose children make use of our school transport service, and the parent's form must show data from only their own child or children. Second is on a form where a school is selected in a drop-down and the hostel dropdown must show only the hostel names for that school. 

The schools and hostels are linked through their respective forms.

I have tried a filter "SchoolID  equals input.School" in the Hostel lookup properties but it returns "No match". The School drop-down displays the school name but the filter "SchoolName equals input.School" says "In Criteria left expression is of type TEXT and right expression is of type NUMBER and the operator == is not valid"