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p.MsoNormal,p.MsoNoSpacing{margin:0}</style></head><body><div>Hi,<br></div><div><br></div><div>Unfortunately, MapServer doesn't have a NULL type.<br></div><div>The workaround is to create a database view or query that will set the NULL to a numeric value of your choosing, e.g. -1 and then use that value in the CLASS expressions.<br></div><div><br></div><div>Seth</div><div><br></div><div id="sig62266145"><div class="signature">--<br></div><div class="signature">web:<a href="https://geographika.net">https://geographika.net</a> & <a href="https://mapserverstudio.net">https://mapserverstudio.net</a><br></div><div class="signature">mastodon: @<a href="mailto:geographika@mastodon.social">geographika@mastodon.social</a><br></div></div><div><br></div><div>On Fri, Mar 28, 2025, at 8:55 AM, Angelique Kroisl via MapServer-users wrote:<br></div><blockquote type="cite" id="qt" style=""><div class="qt-WordSection1"><p class="qt-MsoNormal">Hello,<br></p><p class="qt-MsoNormal">I'm trying to create a class using the class item "gst."<br></p><p class="qt-MsoNormal">The attribute in the database can only have three values (2000, 2100, and <NULL>).<br></p><p class="qt-MsoNormal">Unfortunately, I can't create the NULL EXPRESSION.<br></p><p class="qt-MsoNormal"> <br></p><p class="qt-MsoNormal">I've already tried the following:<br></p><p class="qt-MsoNormal">EXPRESSION IS NULL<br></p><p class="qt-MsoNormal"> <br></p><p class="qt-MsoNormal">EXPRESSION "<NULL>"<br></p><p class="qt-MsoNormal"> <br></p><p class="qt-MsoNormal">EXPRESSION <NULL><br></p><p class="qt-MsoNormal"> <br></p><p class="qt-MsoNormal">EXPRESSION EMPTY<br></p><p class="qt-MsoNormal"> <br></p><p class="qt-MsoNormal">What is the correct syntax for this?<br></p></div><p><br></p><div><hr><br></div><p><br></p><div><span class="font" style="font-family:Arial;">Monatlich aktuelle Informationen Ihrer Stadtverwaltung in unserem Newsletter! <a href="https://www.stadt-koeln.de/service/onlinedienste/newsletter-anmeldung?para=allgemein"> Newsletter Anmeldung</a></span><br></div><div><hr><br></div><p><br></p><p><br></p><div><span class="font" style="font-family:arial;"><br><a href="https://www.stadt-koeln.de/leben-in-koeln/freizeit-natur-sport/veranstaltungskalender/lidl-final4-dhb-pokal"><img src="https://www.stadt-koeln.de/images/footer-final4-2025.jpg"></a></span></div><div>_______________________________________________<br></div><div>MapServer-users mailing list<br></div><div><a href="mailto:MapServer-users@lists.osgeo.org">MapServer-users@lists.osgeo.org</a><br></div><div><a href="https://lists.osgeo.org/mailman/listinfo/mapserver-users">https://lists.osgeo.org/mailman/listinfo/mapserver-users</a><br></div><div><br></div></blockquote><div><br></div></body></html>