diff --git a/sources/application/search/criterionconversion/criteriontooql.class.inc.php b/sources/application/search/criterionconversion/criteriontooql.class.inc.php
index d66f5fd83d..9c6ce953a2 100644
--- a/sources/application/search/criterionconversion/criteriontooql.class.inc.php
+++ b/sources/application/search/criterionconversion/criteriontooql.class.inc.php
@@ -114,21 +114,12 @@ class CriterionToOQL extends CriterionConversionAbstract
 		return addslashes($aValues[$iIndex]['value']);
 	}
 
-	private static function IsEmpty($sValue)
-	{
-		if ($sValue === "0")
-		{
-			return false;
-		}
-		return empty($sValue);
-	}
-
 	protected static function ContainsToOql($oSearch, $sRef, $aCriteria)
 	{
 		$aValues = self::GetValues($aCriteria);
 		$sValue = self::GetValue($aValues, 0);
 
-		if (self::IsEmpty($sValue))
+		if (!strlen($sValue))
 		{
 			return "1";
 		}
@@ -141,7 +132,7 @@ class CriterionToOQL extends CriterionConversionAbstract
 		$aValues = self::GetValues($aCriteria);
 		$sValue = self::GetValue($aValues, 0);
 
-		if (self::IsEmpty($sValue))
+		if (!strlen($sValue))
 		{
 			return "1";
 		}
@@ -154,7 +145,7 @@ class CriterionToOQL extends CriterionConversionAbstract
 		$aValues = self::GetValues($aCriteria);
 		$sValue = self::GetValue($aValues, 0);
 
-		if (self::IsEmpty($sValue))
+		if (!strlen($sValue))
 		{
 			return "1";
 		}
@@ -171,7 +162,7 @@ class CriterionToOQL extends CriterionConversionAbstract
 			return "({$sRef} = '0')";
 		}
 
-		if (self::IsEmpty($sValue) && (!(isset($aCriteria['has_undefined'])) || !($aCriteria['has_undefined'])))
+		if (!strlen($sValue) && (!(isset($aCriteria['has_undefined'])) || !($aCriteria['has_undefined'])))
 		{
 			return "1";
 		}
@@ -184,7 +175,7 @@ class CriterionToOQL extends CriterionConversionAbstract
 		$aValues = self::GetValues($aCriteria);
 		$sValue = self::GetValue($aValues, 0);
 
-		if (self::IsEmpty($sValue))
+		if (!strlen($sValue))
 		{
 			return "1";
 		}