You are developing a consultant search application where by a user looking for a consultant can check all the items in the list they require a consultant to have.
You have 2 tables. consultant and consultant_qual. The consultant_qual has primary key formed by 2 fields consultant_id and qual_id.
qual_id contains a constrained list
with things like 'OpenLayers', 'PostGIS', 'Python', 'C#' etc.
How do you devise a query that given a list of checked options by the user, only returns consultants with not 1 but all of those qualifications?