Or:
coalesce(field, '') in ('', ' ', 'NULL')
Raymond
On 19-01-2023 09:53, kirk via QGIS-User wrote:
You can also use
CASE
When field is null then 123
else 321
end
Kirk Schmidt
Sent from my Galaxy
-------- Original message --------
From: Richard Duivenvoorde via QGIS-User <qgis-user@lists.osgeo.org>
Date: 2023-01-18 1:44 p.m. (GMT-04:00)
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] CSV layer, Time column null expressie to test
for NULL/empty?
Pff, ok found a solution:
"bezoek.begintijd" IS NULL
works
So if I want to test for empty strings, or NULL (like strings), AND real
NULLS, I use now:
( "bezoek.begintijd" IS NULL OR "bezoek.begintijd" in ('', ' ',
'NULL') )
Regards,
Richard Duivenvoorde
On 1/18/23 18:31, Richard Duivenvoorde via QGIS-User wrote:
> We have csv data, which is loaded as layer via the Delimited Text
Layer provider.
>
> The data contains both a date and a time column, which we have to
format as isodatetime using an QGIS Expression.
>
> BUT sometimes time column is empty/no value (in which case we have to
format it as isoTIME only).
>
> So we have to check IF the time column is empty, then only format the
Date, else use Date AND Time.
>
> My problem is that I fail to create an expression for the test IF the
column (see screenshot) is empty.
>
> I thought to use (our column is called "bezoek.begintijd"):
>
> "bezoek.begintijd" in ('', ' ', NULL)
>
> BUT this does NOT return True or False, but NULL !!
>
> But:
>
>
> ("bezoek.begintijd" in ('', ' ', NULL)) = NULL
> does ALSO NOT resolve to True... (also NULL)
>
> When the record has no data (the csv holds no data for that record),
it shows
> <time: >
> if it has data:
> <time: 09:42:00>
>
> Anybody an idea what test I can use to test if the time column (which
is typed as Time) is empty/null/none?
>
> Thanks for any pointers.
>
> Regards,
>
> Richard Duivenvoorde
>
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