On Fri, Nov 16, 2007 at 01:38:30AM -0500, Tom Lane wrote: > Sam Mason <sam@xxxxxxxxxxxxx> writes: > > wow, that's kind of fun isn't it. I only thought you could put a > > constant in there. Maybe I should have had a look in the grammar/tested > > it first! > > IIRC, it used to be restricted to a constant, a few revisions back. > In current releases the only restriction that stems from laziness is > not allowing a sub-select. (If anyone were to put forward a serious > use-case, we'd probably go fix that.) I'm amazed it supports anything more than a constant. The values are almost always going to come from external code, so there doesn't seem much point in doing anything else. I suppose with all the expression evaluation code already in PG, supporting what it currently does isn't hard. > The OP's complaint is that we don't allow a variable of the query's own > level, but AFAICT he's still not grasped the point that that leads to an > indeterminate limit value ... Being too close to a problem makes it very easy to forget about the general case. I probably do this far too often myself! Sam ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
