Update end time and duration in same time, using TIMESTAMPDIFF PHP MYSQL

Question

I want to update ' duration ' and ' end_time ' field in same query/action. ' end_time ' field filled current time, ' duration ' field filled from different minute between ' start ' and ' end_time ' field. when i execute this update, the result in ' duration ' field is 0. How to get end_time and duration in same time.

this is the php code :

<?php
include("koneksi.php");
$id     = $_GET['id'];
$start  = gmdate("Y-m-d H:i:s", time()+60*60*7);
$end_time   = gmdate("Y-m-d H:i:s", time()+60*60*7);
$duration  = $_POST['duration'];


$query = "update billing set end_time='$end_time', duration = TIMESTAMPDIFF(MINUTE, '$start', '$end_time') where id='$id'";

$result = mysql_query($query);
if ($result){
echo '<script language="javascript">window.location = "../?p=los"</script>'; 
} ?>

Answer 1

Duration is being set to 0 because $start and $end_time are the same.

Consider your code:

$start  = gmdate("Y-m-d H:i:s", time()+60*60*7);
$end_time   = gmdate("Y-m-d H:i:s", time()+60*60*7);

$query = "... TIMESTAMPDIFF(MINUTE, '$start', '$end_time') ...";

Because $start == $end_time , the difference will always be 0.

You probably want to use the value of start_time already stored in the database, not the recently created php variable $start . Perhaps something like this:

$query = "
 update billing set 
 end_time='$end_time', 
 duration = TIMESTAMPDIFF(MINUTE, start_time, '$end_time') 
 where id='$id'
";

where start_time is a column in the database.

---

Note: mysql_* functions are deprecated , and you are susceptible to SQL injection . Consider using mysqli or pdo and utilize prepared statements .

Answer 2

thank you for your answer, and this is my fix code

$query = "update billing set , end_time='$end_time', 
 duration = TIMESTAMPDIFF(MINUTE, start, '$end_time'),
 cost = TIMESTAMPDIFF(MINUTE, start, '$end_time') * (SELECT basiccost from costed where id ='1')
 where id='$id'";