[Solved]-Linq SQL error with one-to-many relationship and orderby complex expression-LINQ,C#

i couldn't get around this issue in a single linq statement. my work-around for now is to run the query without my order by clauses and output a list. then in a second statement, apply the order by clauses to that list.

var dogs = _context.dogs.include(d => d.fleas).tolist();
dogs = dogs.orderby(d => d.groomerid.hasvalue).tolist();