How exactly is this done? There's so many questions on stack-overflow about what I'm trying to do; However all of the solutions are to edit the MYSQL Query, and I need to do this from within PHP.
I read about the strtotime('-30 days') method on another question and tried it, but I can't get any results. Here's what I'm trying:
$current_date = date_create();
$current_date->format('U');
... mysql code ...
$transaction_date = date_create($affiliate['Date']);
$transaction_date->format('U');
if($transaction_date > ($current_date - strtotime('-30 days'))) {
} else if(($transaction_date < (($current_date) - (strtotime('-30 days'))))
&& ($transaction_date > (($current_date) - (strtotime('-60 days'))))) {
}
Effectively, I'm trying to sort all of the data in the database based on a date, and if the database entry was posted within the last 30 days, I want to perform a function, then I want to see if the database entry is older than 30 days, but not older than 60 days, and perform more actions.
This epoch math is really weird, you'd think that getting the epoch of the current time, the epoch of the data entry, and the epoch of 30 and 60 days ago would be good enough to do what I wanted, but for some reason it's not working, everything is returning as being less than 30 days old, even if I set the date in the database to last year.
No need to convert to unix timestamp, you can already compare DateTime objects:
$current_date = data_create();
$before_30_day_date = date_create('-30 day');
$before_60_day_date = date_create('-60 day');
$transaction_date = date_create($affiliate['Date']);
if ($transaction_date > $before_30_day_date) {
# transation date is between -30 day and future
} elseif ($transaction_date < $before_30_day_date && $transaction_date > $before_60_day_date) {
# transation date is between -60 day and -30 day
}
This creates (inefficiently, see my comment above) an object:
$current_date = date_create(date("Y-m-d H:i:s"));
From which you try to subtract an integer:
if($transaction_date > ($current_date - strtotime('-30 days'))) {
which is basically
if (object > (object - integer))
which makes no sense.
you're mixing the oldschool time() system, which deals purely with unix timestamps, and the newer DateTime object system, which deals with objects.
What you should have is
$current_date = date_create(); // "now"
$d30 = new DateInterval('P30D'); // 30 days interval
$transaction_date = date_create($affiliate['Date']);
if ($transaction_date > ($current_date->sub($d30)) { ... }
You might consider DatePeriod class, which in essence gives you the ability to deal with a seires of DateTime objects at specified intervals.
$current_date = new DateTime();
$negative_thirty_days = new DateInterval::createFromDateString('-30 day');
$date_periods = new DatePeriod($current_date, $negative_thrity_days, 3);
$thirty_days_ago = $date_periods[1];
$sixty_day_ago = $date_periods[2];
Here you would use $thirty_days_ago, $sixty_days_ago, etc. for your comparisons.
Just showing this as alternative to other options (which will work) as this is more scalable if you need to work with a larger number of interval periods.
Related
I'm really not grasping how dates and times get formatted in PHP for use in mathematical equations. My goal is this;
Get a date and time from the database;
// Get array for times in
$sth = mysqli_query($conn,"SELECT * FROM ledger ORDER BY ID");
$timeins = array();
while($r = mysqli_fetch_assoc($sth)) {
$timeins[] = $r["timein"];
//OR
array_push($timeins, $r['timein']);
}
And then find the distance between the current time and the variable in the array, $timeins[0], and then put the minutes, hours, and days difference in separate simple variables for later use. These variables will be used on their own in if statements to find out if the person has passed certain amounts of time.
edit: the format of the dates being returned from the DB is in the default TIMESTAMP format for MySQL. E.g. 2018-08-06 17:38:37.
It is also possible to perform datetime operations in SQL, to get a difference between two datetime/timestamp values in days, hours, minutes... We can use expressions in the SELECT list, to return the results as columns in the resultset.
Ditching the SELECT * pattern, and specifying an explicit list of expressions that we need returned:
$sql = "
SELECT t.id
, t.timein
, TIMESTAMPDIFF(DAY ,t.timein,NOW()) AS diff_days
, TIMESTAMPDIFF(HOUR ,t.timein,NOW()) AS diff_hours
, TIMESTAMPDIFF(MINUTE ,t.timein,NOW()) AS diff_minute
FROM ledger t
ORDER BY t.id ";
if( $sth = mysqli_query($conn,$sql) ) {
// execution successful
...
} else {
// handle sql error
}
You should use the DateTime class in PHP to do any date manipulation. You can convert a string representation of a MySQL format time to a PHP DateTime object using
$date = DateTime::createFromFormat('Y-m-d H:i:s', $mysqldate);
Also you can create a DateTime object representing the current time using the constructor with no argument:
$now = new DateTime();
To get the difference between two dates as a DateInterval object, use the builtin diff method:
$diff = $now->diff($date);
As a complete example:
$now = new DateTime();
$mysqldate = '2018-04-03 12:30:01';
$date = DateTime::createFromFormat('Y-m-d H:i:s', $mysqldate);
$diff = $now->diff($date);
$diff_days = (int)$diff->format('%a');
$diff_hours = $diff->h;
$diff_minutes = $diff->m;
echo "$diff_days days, $diff_hours hours, $diff_minutes minutes";
Output:
125 days, 9 hours, 4 minutes
Note that you have to use $diff->format('%a') rather than $diff->d to get the days between two dates, as $diff->d will not include the days in any months between the two dates (in this example it will return 3 for today being August 6).
Using the DateTime Class in php is the best way to get accurate results.
$dateNow = new DateTime('now');
$dateIn = DateTime::createFromFormat('d-m-Y H:i:s', $timeins[0]);
$interval = $dateNow->diff($dateIn);
echo $interval->format('%d days, %h hours, %i minutes, %s seconds');
$deltaDays = $interval->d;
$deltaHours = $interval->h;
...
You have to make sure the input format for you DB date is correct, in this case, I assumed d-m-y H:i:s, and then you can output in any format you need as well, as shown in the date docs: http://php.net/manual/en/function.date.php
How can I compute time difference in PHP?
example: 2:00 and 3:30.
I want to convert the time to seconds then subtract them then convert it back to hours and minutes to know the difference. Is there an easier way to get the difference?
Look at the PHP DateTime object.
$dateA = new DateTime('2:00');
$dateB = new DateTime('3:00');
$difference = $dateA->diff($dateB);
(assuming you have >= PHP 5.3)
You can also do it the procedural way...
$dateA = strtotime('2:00');
$dateB = strtotime('3:00');
$difference = $dateB - $dateA;
See it on CodePad.org.
You can get the hour offset like so...
$hours = $difference / 3600;
If you are dealing with times that fall between a 24 hour period (0:00 - 23:59), you could also do...
$hours = (int) date('g', $difference);
Though that is probably too inflexible to be worth implementing.
Check this link ...
http://www.onlineconversion.com/days_between_advanced.htm
I used this to calculate the difference between server time and the users local time. Grab the hour difference and drop that in a form when the user is registering. I then use it to update the time on the site for the user when they do stuff online.
Once I got it working, I switched this line ...
if (form.date1.value == "")
form.date1.value = s;
to ...
form.date1.value = "<?PHP echo date("m/d/Y H:i:s", time()) ?>";
Now I can compare the user time and the server time! You can grab the seconds and mins as well.
I have a table which shows the time since a job was raised.
// These are unix epoch times...
$raised = 1360947684;
$now = 1361192598;
$difference = 244914;
$difference needs to exclude any time outside of business hours (ex, 9-5 and weekends).
How could I tackle this?
The thing you have to do are 3 in numbers.
You take your start date and calculate the rest time on this day (if it is a business day)
You take your end date and calulate the time on this day and
you take the days in between and multiply them with your business hours (just those, that are business days)
And with that you are done.
Find a little class attached, which does those things. Be aware that there is no error handling, time zone settings, daylight saving time, ...
input:
start date
end date
output:
difference time in seconds
adjustable constants:
Business hours
Days that are not business days
Very bad idea, but I had no choice because I'm on php 5.2
<?php
date_default_timezone_set('Asia/Seoul');
$start = 1611564957;
$end = 1611670000;
$res = 0;
for($i = $start; $i<$end; $i++){
$h = date("H", $i);
if($h >= 9 && $h < 18){
//echo date("Y-m-d H:i:s", $i) . "<br>";
$res = $res + 1;
}
}
echo $res;
Use DateTime.
Using UNIX time for this is slightly absurd, and you would have to literally remake DateTime.
Look up relative formats where you can specify the hour on the day, e.g.
$date = new DateTime($raised);
$business_start = new DateTime("09:00"); // 9am today
$business_end = new DateTime("17:00"); // 5pm today
The rest is for you to work out.
Oh, and instead of start/end, you could probably use DateInterval with a value of P8H ("period 8 hours")
The problem with using timestamps directly is that you are assigning a context to a counter of seconds. You have to work backwards from the times you want to exclude and work out their timestamps beforehand. You might want to try redesigning your storage of when a job is raised. Maybe set an expiry time for it instead?
I am developing a quiz site and there is time for x min to answer the quiz. So when user clicks on start quiz link the starttime (current time at this instant) is recored in session. Also the endtime (start_time+ 30 min) is recorded in session and every time he submits a answer the current time is compared with the quiz end time. Only if the current time is less than end_time the answer should be accepted.
How can I get the currentdatetime?
How can I add x minutes to current this datetime?
How can I compare (<=) datetime ?
I think we should use date time. Is it right?
PHP measures time as seconds since Unix epoch (1st January 1970). This makes it really easy to work with, since everything just a single number.
To get the current time, use: time()
For basic maths like adding 30 minutes, just convert your interval into seconds and add:
time() + 30 * 60 // (30 * 60 ==> 30 minutes)
And since they're just numbers, just do regular old integer comparison:
$oldTime = $_SESSION['startTime'];
$now = time();
if ($now < $oldTime + 30 * 60) {
//expired
}
If you need to do more complicated things like finding the date of "next tuesday" or something, look at strtotime(), but you shouldn't need it in this case.
use php builtin functions to get time:
<?php
$currentTimeStamp = time(); // number of seconds since 1970, returns Integer value
$dateStringForASpecificSecond = date('Y-m-d H:i:s', $currentTimeStamp);
?>
for your application that needs to compare those times, using the timestamp is more appropriate.
<?php
$start = time();
$end = $start + (30 * 60); // 30 minutes
$_SESSION['end_time'] = $end;
?>
in the page where the quiz is submitted:
<?php
$now = time();
if ( $now <= $_SESSION['end_time'] ) {
// ok!
}
?>
Use the time() function to get a UNIX timestamp, which is really just a large integer.
The number returned by time() is the number of seconds since some date (like January 1, 1970), so to add $x minutes to it you do something like (time() + ($x*60)).
Since UNIX timestamps are just numbers, you can compare them with the usual comparison operators for numbers (< <= > >= ==)
time() will give you the current time in seconds since 1/1/1970 (an integer), which looks like it should be good.
To add x minutes, you'd just need to add x*60 to that, and you can compare it like any other two integers.
Source: http://us3.php.net/time
This is an old question but I wanted to provide an answer based on the PHP 5.2 DateTime class which I feel is much easier to use and much more versatile than any previous functions.
So how can i get the currentdatetime?
You can create a new DateTime object like this:
$currentTime = new DateTime();
But at this point, $currentTime is a datetime object and must be converted to a string in order to store it in a database or output it.
$currentTime = $currentTime->format('Y-m-d H:i:s');
echo $currentTime;
Outputs 2014-05-10 21:14:06
How can i add x minutes tocurrent this datetime?
You can add x minutes with the modify method:
$currentTime = new DateTime();
$addedMinutes = $currentTime->modify('+10 minutes');
echo $addedMinutes;
Outputs 2014-05-10 21:24:06
How can i comapare (<=) datetime ?
With the DateTime class, you can not only easily compare datetime objects, you can get the difference between them.
$currentTime = new DateTime('2014-05-10 21:14:06');
$addDays = $currentTime->modify('+10 days');
To compare
if ($currentTime >= $addDays) {
//do something//
}
$diffTime = new DateTime('2014-05-10 21:14:06');
$diff = $addDays->diff($diffTime);
$diff = $diff->format('There are %d days difference.');
echo $diff;
Outputs There are 10 days difference.
What is the best (date format independent way) in PHP to calculate difference in days between two dates in specified format.
I tried the following function:
function get_date_offset($start_date, $end_date)
{
$start_time = strtotime($start_date);
$end_time = strtotime($end_date);
return round(($end_time-$start_time)/(3600*24));
}
It works ok on linux box, but when running under windows strtotime returns ''.
EDIT:
Input date is in mm/dd/yyyy format, but I would like to make it accept $format as a parameter.
I need only difference in days.
If you do not want or you cannot use Zend Framework or Pear package try this function i hope this would help:
function dateDifference($date1, $date2)
{
$d1 = (is_string($date1) ? strtotime($date1) : $date1);
$d2 = (is_string($date2) ? strtotime($date2) : $date2);
$diff_secs = abs($d1 - $d2);
$base_year = min(date("Y", $d1), date("Y", $d2));
$diff = mktime(0, 0, $diff_secs, 1, 1, $base_year);
return array
(
"years" => abs(substr(date('Ymd', $d1) - date('Ymd', $d2), 0, -4)),
"months_total" => (date("Y", $diff) - $base_year) * 12 + date("n", $diff) - 1,
"months" => date("n", $diff) - 1,
"days_total" => floor($diff_secs / (3600 * 24)),
"days" => date("j", $diff) - 1,
"hours_total" => floor($diff_secs / 3600),
"hours" => date("G", $diff),
"minutes_total" => floor($diff_secs / 60),
"minutes" => (int) date("i", $diff),
"seconds_total" => $diff_secs,
"seconds" => (int) date("s", $diff)
);
}
The PEAR Date class offers all kinds of features for finding the differences between dates and about 1000 other things as well. The docs for it are here...
The problem with PHP is that it doesn't have a definite DateTime type. You can use a Unix timestamp, or the built-in DateTime class, but they are pretty limited in their functionality. I expect that there should be some 3rd party classes with more extensive support for date-time calculations, but I haven't looked for it.
Using Unix timestamps for date (not time) calculations is also tricky. You'd have to discard the time part, but simply resetting to 00:00 is not safe because of daylight savings time (DST). DST has the effect that there are two days every year that don't have exactly 24 hours. Thus, when adding/subtracting dates you might end up with a value that does not divide evenly with 3600*24.
I'd suggest looking for some 3rd party class that has proper support for all this stuff. Date/Time calculations are awesome in their ugliness. :P
The Zend Framework has the class Zend_Date for dealing with "date math". It works around system specific timestamp limits by using the BCMath extension, or if that's not available limits the timestamps by max float value for your system.
// example printing difference in days
require('Zend/Date.php');
$date1 = new Zend_Date();
$date1->set(2, Zend_Date::MONTH);
$date1->set(27, Zend_Date::DAY);
$date1->set(2008, Zend_Date::YEAR);
$date2 = new Zend_Date();
$date2->set(3, Zend_Date::MONTH);
$date2->set(3, Zend_Date::DAY);
$date2->set(2008, Zend_Date::YEAR);
echo ($date2->getTimestamp() - $date1->getTimestamp()) / (3600*24);
I'm not sure what is considered best, since there is no built-in function in PHP for doing this, but some people have used gregoriantojd(), for example in this forum post.
gregoriantojd() gives the same results as using strtotime(), see this blogpost for how to do it:
http://www.phpro.org/examples/Calculate-Age-With-PHP.html
The following works for me. Believe I found it on the php.net docs somewhere.
*Edit - Woops, didn't see csl's post. This is the exact function from his link, must have been where I found it. ;)
//Find the difference between two dates
function dateDiff($startDate, $endDate)
{
// Parse dates for conversion
$startArry = date_parse($startDate);
$endArry = date_parse($endDate);
// Convert dates to Julian Days
$start_date = gregoriantojd($startArry["month"], $startArry["day"], $startArry["year"]);
$end_date = gregoriantojd($endArry["month"], $endArry["day"], $endArry["year"]);
// Return difference
return round(($end_date - $start_date), 0);
}
I was trying to calculate the difference of two dates for the purpose of showing the duration of an event. Most of the functions given on the problem fails if the event has a duration form friday at 17:00 to sunday at 15:00. My goal was to find the difference between the dates like:
date('Ymd',$end)-date('Tmd',$begining);
But that is likly to fail because there isn't 99 month in a year and 99 days in a month. I could convert the date string to UNIX timestamp and divide by 60*60*12, but some days have a greater or lesser number of hours, sometimes there's eaven a leap secound. So I made my own function using getdate() a function that returns an array of innformation about the timestamp.
/*
* datediff($first,$last)
* $first - unix timestamp or string aksepted by strtotime()
* $last - unix timestamp or string aksepted by strtotime()
*
* return - the difference in days betveen the two dates
*/
function datediff($first,$last){
$first = is_numeric($first) ? $first : strtotime($first);
$last = is_numeric($last ) ? $last : strtotime($last );
if ($last<$first){
// Can't calculate negative difference in dates
return -1;
}
$first = getdate($first);
$last = getdate($last );
// find the difference in days since the start of the year
$datediff = $last['yday'] - $first['yday'];
// if the years do not match add the appropriate number of days.
$yearCountedFrom = $first['year'];
while($last['year'] != $yearCountedFrom ){
// Take leap years into account
if( $yearCountedFrom % 4 == 0 && $yearCountedFrom != 1900 && $yearCountedFrom != 2100 ){
//leap year
$datediff += 366;
}else{
$datediff += 365;
}
$yearCountedFrom++;
}
return $datediff;
}
Concerning the GregorianToJD() function, it might work, but I feel a little bit uneasy since I do not understand how it work.
Let's not overengineer, guys.
$d1 = strtotime($first_date);
$d2 = strtotime($second_date);
$delta = $d2 - $d1;
$num_days = ($delta / 86400);
Calculate the difference between two Dates (and time) using Php. The following page provides a range of different methods (7 in total) for performing date / time calculations using Php, to determine the difference in time (hours, munites), days, months or years between two dates.
See Php Date Time - 7 Methods to Calculate the Difference between 2 dates
PHP 5.2 introduces the DateTime and DateInterval classes which makes this easy:
function get_date_offset($start_date, $end_date)
{
$start_time = new DateTime($start_date);
$end_time = new DateTime($end_date);
$interval = $end_time->diff($start_time);
return $interval->format('%a days');
}