diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 30882fa..2096ffd 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -661,6 +661,10 @@
 				// value appears not to have been set, assign the test to IS NULL
 				$k .= ' IS NULL';
 			}
+			elseif (preg_match('/\s*(!?=|<>)\s*$/i', $k, $match, PREG_OFFSET_CAPTURE))
+			{
+				$k = substr($k, 0, $match[0][1]).($match[1][0] === '=' ? ' IS NULL' : ' IS NOT NULL');
+			}
 
 			$this->{$qb_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
 			if ($this->qb_caching === TRUE)