The issue of possible intoxication could come up if your shooting was not lawful and you were charged. If you are charged, the DA's job is to convict you. He will do anything legal to do so. If the DA thinks that your drinking affected your judgement as to the illegal shooting he would bring try to bring it into evidence. As HankB says, that is one reason not to have Q&A sessions with LEOs where you could make incriminating statements before you consult with your lawyer. Of course it could be used against you in a civil suit if you injured an innocent, but the question was about DAs, not a civil trial.
After reading this thread I am starting to see why so many people are so reluctant to defend themselves again criminals. Constantly hearing statements like "every bullet has a lawyer attached to it" they get so afraid that they will arrested or sued that they think it's better to "take their chances" with the criminals.
What if you were at home drinking the bottle of wine that you bought at the winery and somebody with a gun broke down your door. Are you going to do nothing because you're drinking or are you going to defend yourself? What is the difference if you are outside your house or inside if somebody attacks you with deadly force? In both situations you have a legal right to use deadly force.My opinion is that just one drink affects one's judgment to some extent in such a way that he or she should not have a deadly weapon within reach.
By the way, I don't drink when I am carrying.