Sadly most questions that ask for code are answered, promptly, by passing users more interested in reputation than doing "the right thing". What surprises me is how often those users have 10/20/30k+ reputation.
My rule of thumb is simple - if you haven't posted some kind of code showing what you've tried, you get a close vote. Of course, there are exceptions, but I would expect anyone asking for help converting SQL to LINQ to have tried something themselves.
I leave a comment asking them to show what they've tried so far, but I always immediately close-vote, because often the OP will make no further edits and will just slurp the free answers coming from the masses.
Typical canned comment I have pre-prepared:
Your question doesn't explain what you've done to try and solve the problem; it currently reads like a request for code. Please share your attempted implementation and explain how it fails to meet your requirements.