I stick to standard SQL syntax/features whenever possible as well, but...

Honest question: how often do you switch databases?

I've never really found myself wanting or needing to do this.

Only time I could really see myself wanting to do this is if I was writing some kind of commercial software (eg, a database IDE like DataGrip) that needed to simultaneously support various multiple databases.

    > MySQL

It feels particularly limiting to stick to "standard" SQL for MySQL's sake, since they frequently lag behind on huge chunks of "standard" SQL functionality anyway. For example, window functions (SQL2003 standard) took them about a decade and a half to implement.

We got an application which has been developed for over 20 years with the mentality of "we're never switching db's".

Yet now we are, because some core customers demand MSSQL support...

Of course the db we're using supports all kind of non-standard goodness that has been exploited all over. Gonna be fun times ahead...

Yikes. Good luck with that.

(I don't mean that sarcastically. I truly wish you luck.)

I've done two moves, one from MySQL to Pg and the other from Pg to MySQL. I'm not opposed to leveraging their nonstandard parts where necessary.

Some companies end up with a mix of different DBs and it can help to consolidate to share expertise or resources.

Though at this point both have grown much closer together in capabilities and performance.