My experience is the exact opposite. Only absolutely beginner php/mysql guys do that. And they do so because they don't understand joins. You can't even do outer joins implicitly without vendor specific extensions (which are being deprecated), so the idea that it is better when mixing join types is particularly odd. It is also far from "the standard" in the oracle world. Oracle land has more people who think using weird oraclisms are good, but there's still an awful lot of people who prefer ANSI syntax there. Just look at the answers to questions about it on any forum.