Why does no database fully support ANSI or ISO SQL standards?

Question

If I were designing a oil refinery, I wouldn\'t expect that materials from different vendors would not comply with published standards in subtle yet important ways. Pipework, v

Answer 1

Companies usually tend to use one vendor to avoid having a jungle of different and possibly incompatible systems to support. It's also a lot cheaper to train your developers/system engineers in using one database vendor's tools than in 3 different sets of tools. Later on, this company may then grow large enough to buy some of its competitors. This would mean another entirely different set of tools that you'd have to manage, integrate, etc.

That's a lot of work.

Imagine that instead of that, you have a portability layer so that you really don't care what's beneath. That would be a lot better.