Wiki claims that LEOSA doesn't override GFSZA which makes it sound essentially useless in urban areas (as you're almost always within 1000' of a school, and GFSZA requires state permits).The answer is a solid, it depends. Some states have laws prohibiting guns CCW in bars, etc., some don't. California does not. It is up go department policy. I believe most CA policies have language to the effect that off duty officers, while carrying a firearm, will not consume alcohol to the point it causes impairment. (Or something to that effect. ) This allows for one or two beers or so. However, the federal law that allows officers to CCW out of state is more restrictive as to prohibit alcohol consumption. This is in addition to the states that prohibit CCW in bars, which also applies to off duty LEOs.
So it's legal for me to CCW and have one or two drinks in a bar in California. It's not legal for me to do so out of state.
It prohibits you being under the influence of alcohol, but I don't see a definition of that - I wonder what case law there is, or if it's specified elsewhere.