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I need to identify which features have null attributes in the attribute table of a shapefile. When i try [field]= 'NULL' it selects the features with value=0 (see picture)enter image description here


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It may be a bug. I'll check and let you know, eventually I will link you the ticket URL. Stay tuned. – Giovanni Manghi Oct 24 '11 at 15:26
up vote 30 down vote accepted

Have you tried replacing the "=" with "is"? I don't have QGIS in front of me, but that is pretty common database select syntax for working with NULL values.

pedonal is NULL
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Pedonal = ''

  • that should work!
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that works for text fields...i'm using numerical fields, and that selects values = to 0 – vascobnunes Oct 24 '11 at 15:48
@Darren Cope, NULL is different than "" – artwork21 Oct 25 '11 at 14:25

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