Ühel kenal päeval, R, 2006-05-26 kell 22:50, kirjutas Tom Lane: > I wrote: > > We can use the same technique that we used for UNION JOIN, but instead > > join, say, WITH and TIME into one token and make the time datatype > > productions look for "TIME WITHTIME ZONE" and so on. (I propose this > > rather than putting the ugliness into WITH CHECK OPTION, because this > > way we should only need one merged token and thus only one case to > > check in the filter function; AFAICS we'd need three cases if we > > merge tokens on that end of it.) > > On investigation that turns out to have been a bad idea: if we do it > that way, it becomes necessary to promote WITH to a fully reserved word. > The counterexample is > > CREATE VIEW v AS SELECT * FROM foo WITH ... > > Is WITH an alias for foo (with no AS), or is it the start of a WITH > CHECK OPTION? No way to tell without lookahead. > > While I don't think that making WITH a fully reserved word would cause > any great damage, I'm unwilling to do it just to save a couple of lines > of code.
I think we should go on and do promote WITH to a reserved keyword now because eventually we have to do it anyway. It is needed for recursive queries as well. I don't pretend to be an expert bison coder, but I was unable to define a grammar for SQL-standard recursive queries without making WITH a reserved keyword. -- ---------------- Hannu Krosing Database Architect Skype Technologies OÜ Akadeemia tee 21 F, Tallinn, 12618, Estonia Skype me: callto:hkrosing Get Skype for free: http://www.skype.com ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
