This is a great question. I feel like alcohol impairs my judgment, while tiredness impairs my thinking. In general most day-to-day technical tasks require thinking rather than judgment. Then again, this might just be selection bias because I've never been drunk during business hours (but have been called after hours while drunk) but am frequently asked to weigh in on something right after I sign in but before I've had coffee.
Depends where you are on the Ballmer curve [1], obviously.
Tired by a large margin.
Both is intolerable
Depends on the database.
Drunk = fun
Tired = not fun
I believe it. I can type with perfect spelling and grammar while quite drunk. If I'm half-asleep, it goes right to hell.