Hi Giuseppe,
Thanks for your hint with the syntax - it works in my case.
I think I sort of understand the syntax - at least the > operator and
the substr. What I do not understand is why I need the *-1 (multiplier).
But I think the syntax is far from being intuitive, without some help.
Maybe we can come up with a simple solution in the future?
If we could combine the rule-based renderer approach with the current
labeler (with its new query builder), it would be awesome.
Thanks for your help!
Andreas
On Wed, 28 Dec 2011 20:01:43 +0100, Giuseppe Sucameli wrote:
Hi Andreas,
On Thu, Dec 22, 2011 at 2:31 PM, Andreas Neumann
<[email protected]> wrote:
What I want is that a label is only drawn if a column value is
larger than
0. I don't want to label features with a value of zero.
Do you have any hints how the syntax works for such a case? I see
">"
operators but no "if" or "when".
there's no "if" operator, but ">" returns 1 if true and 0 if false,
e.g. (field > 5)*10 let's give you 10 or 0 as result.
The problem is that you don't want to display anything when
the field value is 0, so we can use the substr function.
Here's the solution to your problem:
substr(id, 0, (id > 0)*-1)
that means if id <= 0 then substr(id, 0, 0) else substr(id, 0, -1)
In general:
substr(output, 0, (condition)*-1)
Cheers.
If it is not possible, then I can still do it in Postgis, but it
would be
nice being able to do this in QGIS.
Thanks for any hints,
Andreas
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8624 Grüt (Gossau ZH)
Switzerland
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Andreas Neumann
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8624 Grüt (Gossau ZH)
Switzerland
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