From a practical standpoint, for anyone who needs to parse SQL today, I can recommend datafusion's sqlparser-rs. This is what we use in http://sql-page.com , and I regularly contribute to it. I don't know anything else that matches its level of support for all the crazy little-known syntax particularities of the various SQL dialects.

In particular, Microsoft SQL Server seems to do everything just a little bit differently, and sqlparser-rs does support its idiosyncrasies most of the time.