PHP check if time range is in a time range - php

Question

I want to insert a time bounded to someone into the database.
For example: Peter 13:00 - 19:00
Peter told us he can't work from 18:00 - 22:00. (This is located in the database).
so the time 13:00 - 19:00 can't be inserted into the database because the end time (19:00) is within the timerange 18:00 - 22:00.
How to check this?
I've tried several things but I dont know how to do it right.
Got this right now
$van_besch = '18:00';
$tot_besch = '22:00';
$van = '13:00';
$tot = '19:00';
if (($van_besch >= $van) && ($tot_besch <= $tot)) {
$error ='<font color="red">Time '.$van_besch.' - '.$tot_besch.' Not available</font>';
}
This won't work.
Thanks for reading!

Answer 1

There are actually two cases you have to check:
$van is equal or between $van_besch and $tot_besch
$tot is equal or between $van_besch and $tot_besch
if $van and $tot are both between $van_besch and $tot_besch both cases are true.
Further more you need to handle shifts that straddle a day break e.g. 17:00 - 02:00. Another problem is you need to handle is 20:00 - 0:00, since 0:00 is smaller than 20:00.
Therefore we project the real time to our own time format.
That means 17:00 - 02:00 will become 17:00 - 26:00. Note that we need to do this for both $van_besch - $tot_besch and $van - $tot$.
In code that would look be something like:
if ($tot < $van){
$tot = 24:00 - $van + $tot;
}
if ($tot_besch < $van_besch){
$tot = 24:00 - $van + $tot;
}
if (($van >= $van_besch) && ($van <= $tot_besch) ) || (($tot >= $tot_besch) && ($tot <= $tot_besch)){
... Peter is not available ...
}

Answer 2

It is better you convert them and compare using strtotime. Something like this would work for you:
$van_besch = '18:00';
$tot_besch = '22:00';
$van = '13:00';
$tot = '19:00';
if (strtotime($van) < strtotime($van_besch) || strtotime($tot ) > strtotime($tot_besch)) {
//code goes here
}

Answer 3

You can handle this in an SQL query for sure. And if you're just storing time, it would be best to do it as an int 0000 - 2359.
So our table would look something like this.
CREATE TABLE off_time (
id int(12) AUTO_INCREMENT,
employee int(12) NOT NULL,
start_time smallInt(4) unsigned NOT NULL,
end_time smallInt(4) unsigned NOT NULL,
PRIMARY KEY (id)
);
We're storing a start and end time to create a block of time that they don't work. Obviously in your code it's important that you makes sure these blocks make sense and start_time <= end_time.
Now we can query.
// Here we use just < and > but you can make them <= and >= if you don't want time slots to possibly overlap start/end times.
SELECT ot.id, IF( 1300 < ot.end_time AND 1900 > ot.start_time, 1, 0) AS blocked
FROM off_time as ot
WHERE ot.employee = 1;
You will get a table back where each row will have the id of the blocked time slot, and a blocked column with 1 meaning it's blocked and 0 meaning it's not. So if any of the entries are 1, then you know your time is blocked out. Doing it this way is also handy because you can also relate a reasons table, and be able to respond with a reason. LEFT JOIN time_off_reasons as r on r.id = ot.id
If you want to be specific with dates. Just store timestamp for start and end times. The comparison will be the same, just with timestamps instead.
EDIT
Marc B. made a good point in the comments about time blocks that stretch over the midnight mark i.e. 2200 - 0200. With my method you would want to make sure you split those apart as separate entries.
So INSERT INTO off_time (start_time, end_time) VALUES(2200, 2400)(0000,0200)
This will still work as expected. But you'll just have two entries for 1 time off block, which might be annoying, but still easier than writing extra code to compensate for the logic.