Reg Me Please wrote:
Il Thursday 15 November 2007 20:28:17 hai scritto:
Reg Me Please wrote:
In my opinion I would say it's more a problem with the syntax checker
that with the planner ("semantics" in my lingo). But I could be wrong.
Well, what it won't let you do is have a subquery in the LIMIT clause.
That's probably due to a combination of:
1. The spec probably says something about it
2. There is an obvious approach involving functions/prepared queries
3. You're the first person to have asked for it.
Now if you can get a couple of hundred to join you at #3, you might have
a feature request :-)
Hmmm ...
It also works with STABLE functions, though.
Well, STABLE means the value won't change during the query.
1. Unluckily I've been too lazy t read the specs.
A wise choice. They're not my idea of fun either.
2. I am not willing to put subqueries there, just need to drive the
"windowing" mechanism by means of a second table (limoff).
And how do you plan to get information from limoff unless it's by a
subquery?
3. Dont' think so :)
The solution I'm using now (two functions) allows for really variable limit
and offset argument. It's just UGLY to write. But it works.
And if it works it should be made available in a easier way (unless the specs
advise otherwhise) with a simple table field (or a function parameter) as the
argument for the LIMIT and for the OFFSET. Maybe with a huge warning about
possible drawbacks with the query planner.
But you're back to subqueries here and the possibility of multiple
values from limoff. Even if you do something like:
SELECT ... LIMIT (SELECT l FROM limoff LIMIT 1)
That doesn't guarantee you one row - you might get zero.
I'll check whether I can drop a feature request, even without undreds of
fellows.
Hey, anyone can request a feature. You're more likely to get it
implemented with a mix of coding skills, money and user-demand though.
--
Richard Huxton
Archonet Ltd
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