Question

I met a issue with LTS
My code as below:

return from p in _db.Companies
where p.Deleted == false &&
(from q in _db.Contacts_Companies
where q.ContactId == contactId && q.Deleted == false
select q.CompanyId).Equals(p.Id)
select p;

I know the issue comes from the CompanyId.Equals(Id)
they are both Int32, but I am a bit confused that Int32 cannot be compared?
If I use Contains, it wont match my requirement.

How could I overcome this issue?

Answer 1

The problem originates with your sub-query:

from q in _db.Contacts_Companies
where q.ContactId == contactId && q.Deleted == false
select q.CompanyId

This doesn’t return an int – it returns (as shown in your error message) IQueryable<int>.

Perhaps you’re caught up on the deferred execution semantics of linq?

Anyway, to solve this you need to convert from the IQueryable<int> to a simple int. Since you’re always expecting exactly one result, I’d suggest adding .First():

return from p in _db.Companies
where p.Deleted == false &&
(from q in _db.Contacts_Companies
where q.ContactId == contactId && q.Deleted == false
select q.CompanyId).First().Equals(p.Id)
select p;