diff --git a/Tests/dblayerooComplet.php b/Tests/dblayerooComplet.php
index b7d48af..37eefcb 100644
--- a/Tests/dblayerooComplet.php
+++ b/Tests/dblayerooComplet.php
@@ -1047,4 +1047,15 @@ class test_dblayeroo_{ENGINE} extends PHPUnit_Framework_TestCase
       'groups' => 'group1,group2'
     )), $res);
   }
+
+  public function test_GROUPCONCATwithAlias3 ()
+  {
+    $tbl1 = $this->tbl1 ();
+    $res = $tbl1->select ()
+                ->displayAdd ("GROUP_CONCAT(group,' ')", "groups")
+                ->execute ();
+    $this->assertSame (array (array (
+      'groups' => 'group1 group2'
+    )), $res);
+  }
 }
diff --git a/dblayeroo.php b/dblayeroo.php
index bd979cf..8674e46 100644
--- a/dblayeroo.php
+++ b/dblayeroo.php
@@ -1552,10 +1552,37 @@ class dblayeroo
         "Invalid aliasNames provided (not string and not array)");
     if (is_string ($columnNames))
     {
-      // Remove the GROUP_CONCAT(col,',') as ',' is the default and the comma
-      // will be counted in error
-      $columnNames = str_replace (",','", "", $columnNames);
-      $columnNames = explode (",", $columnNames);
+      // A string must be separated by comma. But comma can be also in function
+      // parameter like GROUP_CONCAT(group,','),field1,field2
+      // This block will explode on comma but only if not in a parenthesis block
+      $tmpArr = array ();
+      $parenthesis = false;
+      $tmp = "";
+      for ($i = 0 ; $i < strlen ($columnNames) ; $i++)
+      {
+        $char = $columnNames{$i};
+        if ($parenthesis === true)
+        {
+          $tmp .= $char;
+          if ($char === ")")
+            $parenthesis = false;
+        }
+        elseif ($char === "(")
+        {
+          $tmp .= $char;
+          $parenthesis = true;
+        }
+        elseif ($char === ",")
+        {
+          $tmpArr[] = $tmp;
+          $tmp = "";
+        }
+        else
+          $tmp .= $char;
+      }
+      if ($tmp !== "")
+        $tmpArr[] = $tmp;
+      $columnNames = $tmpArr;
     }
     if (is_string ($aliasNames))
       $aliasNames = explode (",", $aliasNames);
@@ -1598,13 +1625,17 @@ class dblayeroo
             // There is a comma: the developper add the separator string
             $separator = addslashes (substr ($name, $pos + 2, -1));
             $name = substr ($name, 0, $pos);
-            if ($this->driver === "sqlite" || $this->driver === "psql")
+            if ($this->driver === "sqlite" || $this->driver === "pgsql")
               $separator = ",'$separator'";
             elseif ($this->driver === "mysql")
               $separator = " SEPARATOR '$separator'";
           }
           if ($func === "GROUP_CONCAT" && $this->driver === "pgsql")
+          {
             $func = "string_agg";
+            if ($separator === "")
+              $separator = ", ','";
+          }
         }
       }
       $fieldName = $name;
@@ -1625,8 +1656,6 @@ class dblayeroo
       {
         // For Postgres, the entry must be :
         // string_agg(distinct "group"::character varying, ',' order by "group")
-        if ($separator == "")
-          $separator = ", ','";
         $this->displayColumn[$getSortOrder] =
           "$func($distinct$this->sep$fieldName$this->sep".
           "::character varying$separator ".