[Qgis-user] Query expression bugs with NULL Values

[José Carlos Martínez Llario]

Thanks for the answer Jürgen, didnt know that QGIS used normal database 
null logic which is fantastic.
Cheers,
Jose


On 26/03/2015 10:53, Jürgen E. Fischer wrote:
> Hi José,
>
> On Thu, 26. Mar 2015 at 10:19:10 +0100, José Carlos Martínez Llario wrote:
>> "amenity"  <>  'restaurant' returns 37 rows
>> "amenity"  =  'restaurant'  returns 11 rows
>>
>> The layers has 48 NULL values, so it means that amenity"  <>
>> 'restaurant' does not take into account the null values.
>> Hope this is a bug and not the correct behaviour.
> It's the correct behaviour.   NULL <> 'restaurant' is NULL, ie. not true.
>
> Use eg. coalesce('amenity','') <> 'restaurant'
>
>
> Jürgen
>
>
>
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-- 
------------------------------
José Carlos Martínez Llario
http://cartosig.upv.es

Producción Cartográfica y SIG.
Dpto. Ingeniería Cartográfica.
Univ. Politécnica de Valencia.
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