Dynamic Queries (Where Clauses etc.)

Hello,I am trying to design an application where the user can define filter parameters from a Windows forms application. For e.g. the user may define criteria for:1. Date of Birth 2. Address.ZipCode = 902103. InterestId = '123'These filtering criteria would differ for each customer order. I have a common data model defined so querying will pretty much be within a given set of entities/tables.I would even like to create groupings with AND OR criteria etc.I have been considering multiple approaches to solve this problem. I haven't been able to nail down a clean method for doing so yet.Here are a couple of approaches:1. Create manual code for SQL using string concatenations2. Using LINQ Expressions for Linq to sql.The approach 2 looks really nice but falls short when I need to query for aggregate properties for e.g. queries like:from p in context.Productswhere p ...