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

IMHO, the DB vendors push forward the ANSI SQL standards to include new features & constructs within their field much more than ANSI telling the DB vendors the "one true way".

The DB market is driven by features, scalability and cost. It is not a commercial priority to forego and delay a technical advantage (i.e. partitioning, pivot, UPSERT, replication) by waiting for ANSI to ratify the syntax. By the time that has been done, there is already a significant installation of the proprietary syntax.

That being said, most DB vendors have improved their core "ANSI SQL" support greatly in the last few years. (SQL Server with the SELECT FROM INFORMATION_SCHEMA and Oracle's ANSI joins actually working as well as native joins under the CBO)