php - PHP 複数のパラメータを切り替える

Question

これをより組織的に見せる方法はありますか？

if (!isset( $par2 ) && !isset( $par3 )) {
        $where = "lvlOne = '".$par1."'";

    } elseif(isset( $par2 ) && !isset( $par3 )) {
        $where = "lvlOne = '".$par1."' AND lvlTwo = '".$par2."'";

    } elseif(isset( $par2 ) && isset( $par3 )) {
        $where = "lvlOne = '".$par1."' AND lvlTwo = '".$par2."' AND lvlThree = '".$par3."'";
    }

Answer 1

 $where = "lvlOne = '{$par1}'";
if (isset( $par2 )) { $where .= " AND lvlTwo = '{$par2}'"; } 
if(isset( $par3 )) { $where .= "AND lvlTwo = '{$par2}' AND lvlThree = '{$par3}'";  }