[Qgis-user] CSV layer, Time column null expressie to test for NULL/empty?

[Richard Duivenvoorde]

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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