Remove _limit()'s extra parameters and qb_limit, qb_offset unneeded typecasts + add _compile_group_by() method
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index 10306d7..43ea100 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -1130,7 +1130,7 @@
 		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
 			.$this->_compile_where()
 			.(empty($this->qb_orderby) ? '' : ' ORDER BY '.implode(', ', $this->qb_orderby))
-			.($this->qb_limit ? ' LIMIT '.(int) $this->qb_limit : '');
+			.($this->qb_limit ? ' LIMIT '.$this->qb_limit : '');
 	}
 
 	// --------------------------------------------------------------------