diff --git a/src/Compat/FilterProcessor.php b/src/Compat/FilterProcessor.php
index 85aebe7..b6c9bdc 100644
--- a/src/Compat/FilterProcessor.php
+++ b/src/Compat/FilterProcessor.php
@@ -4,7 +4,6 @@
 
 use InvalidArgumentException;
 use ipl\Sql\Filter\Exists;
-use ipl\Sql\Filter\IsNull;
 use ipl\Sql\Filter\NotExists;
 use ipl\Sql\Sql;
 use ipl\Stdlib\Filter;
@@ -101,13 +100,11 @@ public static function assemblePredicate(Filter\Condition $filter)
                 $operator = 'EXISTS';
             } elseif ($filter instanceof NotExists) {
                 $operator = 'NOT EXISTS';
-            } elseif ($filter instanceof IsNull) {
-                $operator = 'IS NULL';
             } else {
                 throw new InvalidArgumentException(sprintf('Cannot render filter: %s', get_class($filter)));
             }
 
-            return $expression !== null ? ["$column $operator ?" => $expression] : ["$column $operator"];
+            return ["$column $operator ?" => $expression];
         }
     }
 }
diff --git a/src/Filter/IsNull.php b/src/Filter/IsNull.php
deleted file mode 100644
index 1f9c316..0000000
--- a/src/Filter/IsNull.php
+++ /dev/null
@@ -1,13 +0,0 @@
-<?php
-
-namespace ipl\Sql\Filter;
-
-use ipl\Stdlib\Filter\Condition;
-
-class IsNull extends Condition
-{
-    public function __construct($column)
-    {
-        parent::__construct($column, null);
-    }
-}