On Fri, 1 Mar 2019 13:44:57 +0530 Rocky Ji <[email protected]> wrote:
> So for learning sake, is there a tool that converts a query using > `WHERE` to a query (that yields identical results) using JOINs? Like > a English -> <AnyLanguage> side-by-side translator. SQL-92 was introduced a long time ago. At that time, I don't remember any vendor offering any kind of automatic conversion tool. Nor do I know of one now. It's not that it couldn't be done. It's that it wouldn't help. Given a database schema and a query, it's no problem to separate join criteria from (relational) select criteria. But equivalent translations could be expressed several ways, and no machine-generated conversion would necessarily communicate the intention of the query any better. Put another way: how likely is a machine to better pose a query than the human being did in first place? If automatic translation adds functionality, that's different. For example, Oracle had a tool to convert T-SQL to PL/SQL. While the output was no one's concept of beauty, it did have the property of running on Oracle. The most important contribution of SQL-92 to the SELECT statement, as I think Keith mentioned, wasn't separating JOIN from WHERE, but a clear, standardized outer-join syntax. --jkl _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
