Fix sort order when contact name is empty

program/include/rcube_contacts.php

@@ -184,7 +184,7 @@ class rcube_contacts extends rcube_addressbook
                 " AND c.user_id=?" .
                 ($this->group_id ? " AND m.contactgroup_id=?" : "").
                 ($this->filter ? " AND (".$this->filter.")" : "") .
-            " ORDER BY c.name, c.email",
+            " ORDER BY ". $this->db->concat('c.name', 'c.email'),
             $start_row,
             $length,
             $this->user_id,

program/include/rcube_mdb2.php

@@ -600,6 +600,32 @@ class rcube_mdb2
         }
     }
 
+    /**
+     * Abstract SQL statement for value concatenation
+     *
+     * @return string SQL statement to be used in query
+     * @access public
+     */
+    function concat(/* col1, col2, ... */)
+    {
+        $func = '';
+        switch($this->db_provider) {
+            case 'mysql':
+            case 'mysqli':
+                $func = 'CONCAT';
+                $delim = ', ';
+                break;
+            case 'mssql':
+            case 'sqlsrv':
+                $delim = ' + ';
+                break;
+            default:
+                $delim = ' || ';
+        }
+        
+        return $func . '(' . join($delim, func_get_args()) . ')';
+    }
+
 
     /**
      * Encodes non-UTF-8 characters in string/array/object (recursive)