public function sortBy($columnName, $asc = TRUE) {

		$sort = new \stdClass();

		$sort->column = $columnName;
		$sort->asc = !!$asc;

		$this->columnSorts[] = $sort;

		return $this;

	}
public function sortBy($columnName, $asc = TRUE) {

		$sort = new \stdClass();

		$sort->column = $columnName;
		$sort->asc = !!$asc;

		$this->columnSorts[] = $sort;

		return $this;

	}
public function sortBy ( $ columnName , $ asc = TRUE ) { $ sort = new \ stdClass ( ) ; $ sort -> column = $ columnName ; $ sort -> asc = ! ! $ asc ; $ this -> columnSorts [ ] = $ sort ; return $ this ; }
add ORDER BY clause

@param string $columnName
@param boolean $asc

@return \vxPHP\Orm\Query
add ORDER BY clause