diff --git a/composer.json b/composer.json
index cd5a27d..2b5a7e4 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,8 @@
         "robmorgan/phinx": "0.5.*",
         "monarc/core": "dev-master",
         "monarc/frontoffice": "dev-master",
-        "phing/phing": "~2.0"
+        "phing/phing": "~2.0",
+        "beberlei/DoctrineExtensions": "^1.0"
     },
     "config": {
         "bin-dir": "bin/"
diff --git a/config/autoload/global.php b/config/autoload/global.php
index e8fc108..44caa2e 100644
--- a/config/autoload/global.php
+++ b/config/autoload/global.php
@@ -74,6 +74,7 @@ return array(
                 'configuration' => 'orm_cli',
             ),
         ),
+        // https://github.com/beberlei/DoctrineExtensions/blob/master/config/mysql.yml
         'configuration' => array(
             'orm_default' => array(
                 'metadata_cache'        => 'mycache',
@@ -85,7 +86,9 @@ return array(
                 'proxy_namespace'       => 'DoctrineORMModule\Proxy',
                 'filters'               => array(),
                 'datetime_functions'    => array(),
-                'string_functions'      => array(),
+                'string_functions'      => array(
+                    'greatest' => 'DoctrineExtensions\Query\Mysql\Greatest',
+                ),
                 'numeric_functions'     => array(),
                 'second_level_cache'    => array(),
             ),
@@ -99,7 +102,9 @@ return array(
                 'proxy_namespace'       => 'DoctrineORMModule\Proxy',
                 'filters'               => array(),
                 'datetime_functions'    => array(),
-                'string_functions'      => array(),
+                'string_functions'      => array(
+                    'greatest' => 'DoctrineExtensions\Query\Mysql\Greatest',
+                ),
                 'numeric_functions'     => array(),
                 'second_level_cache'    => array(),
             ),