diff --git a/CHANGELOG.md b/CHANGELOG.md
index 429de175..eab06bb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,9 +5,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [UNRELEASED]
+
+### Fixed
+
+- Fix `search option` for `multiple` dropdown
+
 ## [1.21.23] - 2025-08-26
 
-- FIx undefined array key `multiple_dropdown_action` during import
+### Fixed
+
+- Fix undefined array key `multiple_dropdown_action` during import
 - Fix incompatibility of `multiple` dropdowns with `massiveaction`
 - Fix default value properly applied in multiple dropdown search options
 - Fix `search option` for default values in `multiple` dropdown
@@ -15,11 +23,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - The field name was empty in the GLPI logs
 
 ### Added
+
 - Add `replace` and `add` options in massive action for the multiple dropdowns fields
 
 ## [1.21.22] - 2025-05-28
 
 ### Fixed
+
 - Fix condition check logic for dropdown field values
 - Fix validation for mandatory multiple dropdown
 - Fix `twig` error about undefined `dropdown_options`
diff --git a/hook.php b/hook.php
index a7c5699a..e1683f12 100644
--- a/hook.php
+++ b/hook.php
@@ -400,9 +400,9 @@ function plugin_fields_addWhere($link, $nott, $itemtype, $ID, $val, $searchtype)
         $tablefield = "$table" . '_' . "$field";
         switch ($searchtype) {
             case 'equals':
-                return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'notequals' : 'equals', $itemtype, $field_field);
+                return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'notequals' : 'equals', $field_field);
             case 'notequals':
-                return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'equals' : 'notequals', $itemtype, $field_field);
+                return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'equals' : 'notequals', $field_field);
         }
     } else {
         // if 'multiple' field with cleaned name is found -> 'dropdown' case
@@ -420,9 +420,9 @@ function plugin_fields_addWhere($link, $nott, $itemtype, $ID, $val, $searchtype)
         ) {
             switch ($searchtype) {
                 case 'equals':
-                    return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'notequals' : 'equals', $itemtype, $field_field);
+                    return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'notequals' : 'equals', $field_field);
                 case 'notequals':
-                    return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'equals' : 'notequals', $itemtype, $field_field);
+                    return PluginFieldsDropdown::multipleDropdownAddWhere($link, $tablefield, $field, $val, $nott ? 'equals' : 'notequals', $field_field);
             }
         } else {
             return false;
diff --git a/inc/dropdown.class.php b/inc/dropdown.class.php
index 926b670a..02d092d4 100644
--- a/inc/dropdown.class.php
+++ b/inc/dropdown.class.php
@@ -255,32 +255,26 @@ public static function getClassname($system_name)
         return 'PluginFields' . ucfirst($system_name) . 'Dropdown';
     }
 
-    public static function multipleDropdownAddWhere($link, $tablefield, $field, $val, $searchtype, $itemtype, $field_field)
+    public static function multipleDropdownAddWhere($link, $tablefield, $field, $val, $searchtype, $field_field = [])
     {
         /** @var \DBmysql $DB */
         global $DB;
 
-        $default_value_request = "";
-
-        if ($field_field->fields['default_value'] === '["' . $val . '"]') {
-            switch ($searchtype) {
-                case 'equals':
-                    $default_value_request = ' OR (' . $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName('itemtype') . ' IS NULL' .
-                    ' AND ' . $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName('items_id') . ' IS NULL)';
-                    break;
-                case 'notequals':
-                    $default_value_request = ' AND (' . $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName('itemtype') . '=' . $DB->quoteValue($itemtype) .
-                    ' OR ' . $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName('items_id') . '=' . $itemtype::getTable() . '.id)';
-                    break;
-            }
-        }
+        // Determines the default value
+        $default_value = $field_field->fields['default_value'] ?? '';
+        $default_value = ($default_value == '[]') ? '' : $DB->quoteValue($default_value);
 
-        switch ($searchtype) {
-            case 'equals':
-                return $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName($field) . ' LIKE ' . $DB->quoteValue("%\"$val\"%") . $default_value_request;
-            case 'notequals':
-                return $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName($field) . ' NOT LIKE ' . $DB->quoteValue("%\"$val\"%") .
-                ' OR ' . $link . $DB->quoteName($tablefield) . '.' . $DB->quoteName($field) . ' IS NULL' . $default_value_request;
-        }
+        // Constructs the SQL query base
+        $quotedField = $DB->quoteName($tablefield) . '.' . $DB->quoteName($field);
+        $sqlBase = $link . ' COALESCE(' . $quotedField . ', ' . $default_value . ')';
+
+        // Handles “equals” and “notequals” cases in a unified manner
+        $operator = ($searchtype === 'equals') ? '' : 'NOT ';
+        $condition = ($val == '0')
+            ? $operator . 'IN("", "[]")'
+            : $operator . 'LIKE ' . $DB->quoteValue("%\"$val\"%");
+
+        return $sqlBase . ' ' . $condition;
     }
+
 }