The SQL standard defines more of an aesthetic than an actual language. Every database just extends it arbitrarily and anything beyond rudimentary queries is borderline guaranteed to be incompatible with other databases.

When it comes to procedural logic in particular… you have almost zero chance you’re dropping into that into another database and it working — even for rudimentary usage.

SQL-land is utterly revolting if you have any belief in standards being important. Voting for Oracle (itself initialized as a shallowly copied dialect of IBM SQL, and deviated arbitrarily) as the thing to call “standard” is just offensive.