Pair program with your graduate candidates. Do they work well with you? Are they flexible? Do they have mastery of typing and editing code? If yes - then hire

Pair program with your graduate candidates. Do they work well with you? Are they flexible? Do they have mastery of typing and editing code? If yes - then hire them. Don't hire people based off programming riddles. Don't hire people because they know an SQL join - hire people who can come up to speed with SQL in a reasonable amount of time. Industry has a responsibility to teach good coding practices. That's just the way it is.