如何改变我的变量从秒到分钟


how to changes my variable from seconds to minutes

在下面的代码中,我在字段名date_time中减去用户John的前一个日期从当前日期CURRENT_TIMESTAMP变量$newdate只以秒为单位回显答案我如何使它显示从秒到分钟从分钟到小时然后从小时到天

$query1 = "
    SELECT (CURRENT_TIMESTAMP - date_time) AS dnew, date_time
    FROM user
    WHERE name = 'john'
";
$result1 = mysql_query ($query1) or die('query error2');
$line = mysql_fetch_assoc($result1);
$newdate = $line[dnew];
echo "$newdate"; 
$query1 = "
    SELECT (CURRENT_TIMESTAMP - date_time) * 60 AS dnew, date_time
    FROM user
    WHERE name = 'john'
";

use math (* 60)