Contains inside Linq-to-Entities

Question

I need to implement search by term and store in IQueryable but Entity Framework doesn't allow to use Contains method in Linq-to-Entities, how can I replace it?

query = query.Where(e => e.Fullname.Contains(searchTerm, StringComparison.InvariantCultureIgnoreCase) ||
                         e.Email.Contains(searchTerm, StringComparison.InvariantCultureIgnoreCase) ||
                         e.Username.Contains(searchTerm, StringComparison.InvariantCultureIgnoreCase));

Answer 1

remove StringComparison.InvariantCultureIgnoreCase

query = query.Where(e => e.Fullname.Contains(searchTerm) || 
                         e.Email.Contains(searchTerm) ||
                         e.Username.Contains(searchTerm));

Linq to SQL translates Contains("searchterm") into like '%searchterm%' which is case insensitive

Answer 2

Entity Framework Core has a built in function EF.Functions in the Microsoft.EntityFrameworkCore namespace. You could use it as such

query = query.Where(e => EF.Functions.FreeText(e.Fullname, searchTerm) || EF.Functions.Contains(e.Email, searchTerm)); //etc

Note. To use this function FullTextSearch index should be configured on the table columns. I personally use Postgres and this is the documentation on how to configure FullTextSearch index on an entity. Find out how to configure such indexes from you provider.