On 7 Jul 2016, at 3:37pm, Josef Kučera <jokusoftw...@gmail.com> wrote:
> Imagine a query like "SELECT A.F1, B1.F FROM A JOIN (SELECT F2 AS F FROM B > WHERE F3=0) B1". If the query flattener is active the result-set has columns > "A.F1" and "B1.F". If it is disabled the result-set columns are "F1" and "F". > The "short_column_names" option is set. > > I thought the optimization used, would not change the result-set column > names. Was I wrong? Yes. There is no documentation for result-set column names unless you specify them using "AS". They can be anything, and they can change from one version of SQLite to another. Never rely on them unless you're using "AS". Also, your natural JOIN (sometimes called ANSI JOIN) is a little dangerous since it can collapse if you change column names or definitions. People have been complaining about the problem for over a decade. An example is when a program stops working because someone added 'info' columns to both tables and the JOIN command is now looking only for cases where they match. It's better to define the connection between the two tables explicitly. I would hope to see something more like SELECT A.F1, B.F FROM A JOIN B ON B.x = A.y This lets you define column names all in one place more neatly: SELECT A.F1 AS F1, B.F AS F1 FROM A JOIN B ON B.x = A.y rather than having to put some "AS" at the beginning and other "AS" in the sub-select. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
