diff --git a/dblayeroo.php b/dblayeroo.php
index 76ecc72..e4d2937 100644
--- a/dblayeroo.php
+++ b/dblayeroo.php
@@ -4,6 +4,8 @@
   * @author Dominique Fournier <dominique@fournier38.fr>
   */
 
+require_once ("domframework/dblayeroo.php");
+
 // dblayeroo.php
 
 /** Permit abstraction on the differents SQL databases available */
@@ -2044,10 +2046,39 @@ class dblayeroo
        $this->DBException (sprintf (
          "Invalid field to join '%s' : not defined in Local table",
          $fieldLocal));
-      if (! array_key_exists ($fieldToJoin, $object->fields))
-       $this->DBException (sprintf (
-         "Invalid field to join '%s' : not defined in Distant table",
-         $fieldToJoin));
+      if (substr ($fieldToJoin, 0, 7) === "CONCAT(")
+      {
+        if (substr ($fieldToJoin, -1) !== ")")
+          $this->DBException ("CONCAT without ending parenthesis");
+        $tmp = substr ($fieldToJoin, 7, -1);
+        $new = "CONCAT(";
+        foreach (explode (",", $tmp) as $part)
+        {
+          if ($new !== "CONCAT(")
+            $new .= ",";
+          if (substr ($part, 0, 1) === "'" &&
+              substr ($part, -1) === "'")
+            $new .= $part;
+          elseif (! array_key_exists ($part, $object->fields))
+            $this->DBException (sprintf (
+              "Invalid field to join in CONCAT : ".
+              "'%s' not defined in Distant table", $part));
+          else
+            $new .=
+              $this->sep.$object->tableprefix.$object->table.$this->sep.".".
+              $this->sep.$part.$this->sep;
+        }
+        $new .= ")";
+        $joinArray[$fieldLocal] = $new;
+      }
+      elseif (! array_key_exists ($fieldToJoin, $object->fields))
+        $this->DBException (sprintf (
+          "Invalid field to join '%s' : not defined in Distant table",
+          $fieldToJoin));
+      else
+        $joinArray[$fieldLocal] =
+          $this->sep.$object->tableprefix.$object->table.$this->sep.".".
+          $this->sep.$fieldToJoin.$this->sep;
     }
     if (! isset ($object->table) || $object->table === null ||
         trim ($object->table) === "")
@@ -2066,9 +2097,7 @@ class dblayeroo
       $tmp .=
         $this->sep.$this->tableprefix.$this->table.$this->sep.".".
         $this->sep.$fieldLocal.$this->sep.
-        "=".
-        $this->sep.$object->tableprefix.$object->table.$this->sep.".".
-        $this->sep.$fieldToJoin.$this->sep;
+        "=$fieldToJoin";
     }
     // Correct the displayQuery in the main display fields with the display
     // fields of object