PHP // Converting/Calculating DATE

Question

Im trying to solve this since two days without success... First of all my code:

PHP-Version: 5.4

SCRIPT1:

query = "SELECT start, end FROM timetable WHERE ........";
$result = mysql_query($query, $db) or die(mysql_error());
$sqlarr = mysql_fetch_array($result, MYSQL_ASSOC);
$times  = array($sqlarr['start'], $sqlarr['end']);

$calced = strtotime($times[1]) - strtotime($times[0]);
$total = date("H:i:s", $calced-3600);            //<-- -3600 Fixed it
echo "<br>Total: ".$total;

The start and end times are in format 00:00:00. Everytime this script calculates it appends 1 hour to the result. So if im going for a result of 5 minutes i´ll get 01:00:05. Why???

This one is even more strange. SCRIPT2:

while($row = mysql_fetch_array($result, MYSQL_ASSOC)){
    echo " | ".$row['total']."<br>";
    $add += strtotime($row['total']);}

echo $add;

The first script calculates the total time from start to end. The second one should get the total-times out of the db and calculate the sum of all entries. For every entry the second script substracts 2 hours.

Example: Database => Start = 12:32:00 End = 12:32:15

Script1 Result1 = 01:00:15 (Where is this extra hour coming from?) FIXED

Every Result1 is stored in the same table(db). Script2 is loading all this rows and handling them by a while-loop.

According to how many entries there are the script subtracts serval hours.
0 Entries => Total: 00:00:00
1 Entry => Total: 23:00:xx
2 Entries => Total: 20:00:xx
3 Entries => Total: 18:00:xx
4 Entries => Total: 16:00:xx
So, with 2 entries it continues subtracting 2 hours from every total-calculation which isnt correct, abviously.

Thanks to you guys. Using DateTime made this simple and bugfree!

So I didn't really get it, 00:00:05 + 00:00:05 = 22:00:10, what is start and end in this example? So start = 00:00:10 and end = 22:00:10? — Artemkller545
– Artemkller545, Commented May 23, 2014 at 7:51

Community · Accepted Answer · 2023-11-17 20:42:18Z

2

I am not really sure of your case with using strtotime function, but I've tried this solution and it worked, if you have php > 5.2:

You can use the DateTime class and date_diff function to get the difference date, read more here: https://www.php.net/manual/en/datetime.diff.php

Example:

// start date
$start = new DateTime("09:23:38");
// end date
$end = new DateTime("09:23:54");

// calculate difference
$calc = date_diff($start, $end);

// prints 00:00:16
echo $calc->format('%h:%i:%s');

According to this answer It seems like by default date starts from 1:00:00 so you could subtract your date by 3600 seconds (1 hour) like this:

$start = strtotime("11:23:38");
$end = strtotime("11:23:54");

$calc = $end - $start;
echo date('H:i:s', $calc - 3600);

edited Nov 17, 2023 at 20:42

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answered May 23, 2014 at 8:11

Artemkller545

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3 Comments

C4d Over a year ago

Im a newbie with converting and calculating with dates and times. I tried this on a testpage. Worked for now. I get 0:0:x. Is it possible to get this into 00:00:xx?

C4d Over a year ago

Alright. -3600 fixed my first problem. There is now still the second one. The "total-times" are stored together in 1 table. The 2nd script loads all the entries and sumarizes them. For every entry in my table the end-result gets substraced by 2 hours. I hope you know what I mean.

Artemkller545 Over a year ago

If I get you correctly, that's because you subtract 2 time differences, so each time difference has +3600 extra. try doing totaltime - (3600 * amountOfDifferences).

Rybus · Accepted Answer · 2014-05-23 08:47:20Z

0

The problem comes from :

 echo date('H:i:s', $calc);

$start - $end gives you the expected value in seconds. It depends on what value date('H:i:s', 0) is. On my computer, it's not midnight on 1 jan. 1970 ! This link as example : http://sandbox.onlinephpfunctions.com/code/81e56cbce16f6dacfedd2cb376b946a540bce36d.

You might consider substracting date('H:i:s', 0) from your result to get correct value.

Or using DateTime as @Ben Beri suggested you to do as it is (I think) the best way to do.

answered May 23, 2014 at 8:47

Rybus

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