help regarding dates

greedyisg00d

Hi I am just new to php I am currently developing an scheduler for meetings,conference etc. I have a $date_from and $date_to variable in my code which is stored in my database.

For example:
Date From:04-Feb-2009
Date To: 08-Feb-2009

My problem is I do not know the logic on how can I retrieve the dates in between (Feb, 5,6,7) and store it in the database. Any idea how it works? Thanks

Installer

Format your dates according to the mysql date format, then

$query = "SELECT * FROM my_table WHERE date_field > '$date_from' AND date_field < '$date_to'";

greedyisg00d

Hi it seems that your code will work if I have a table of all the dates in my database. But in default what I need is to first retrieve all the dates in between and insert these dates into my database which I think require a lot of code especially when the range between the two dates is huge. Thanks

Installer

This will give you an array of dates:

function dates_between($from_ts, $to_ts, $inclusive = false, $format = 'Y-m-d')
{
    $arr = array();
    if ($from_ts > $to_ts) {
        list($from_ts, $to_ts) = array($to_ts, $from_ts);
    }
    while (($from_ts = strtotime('+1 day', $from_ts)) < $to_ts) {
        $arr[] = date($format, $from_ts);
    }
    if ($inclusive) {
        array_unshift($arr, date($format, $from_ts));
        $arr[] = date($format, $to_ts);
    }
    return $arr;
}

$date_from = '2009-02-04';
$date_to   = '2009-02-08';
$between = dates_between(strtotime($date_from), strtotime($date_to));
if (!empty($between)) {
    foreach ($between as $each) {
        echo $each . '<br />';
    }
}

You can specify the dates in reverse order, even. And you can get an "inclusive" range by setting the third argument to true.

greedyisg00d

Thanks men your code works fine...Another thing is it is good if I store the dates_between in my database? This is my scenario, for example the employee greedyisgood is set for a trip from 2009-02-04 up to 2009-02-08. Thus when the secretary selects a specific date 2009-02-06 for the meeting, the employee greedyisgood will not be shown on the list since the date specified is in between 2009-02-04 up to 2009-02-08. Is this possible?

Installer

Yes, it's possible, sounds like something you could use the MySQL functions "BETWEEN" and "NOT BETWEEN" for.

While I'm posting, the dates_between() function I posted before has a bug in it. Here's the correction:

function dates_between($from_ts, $to_ts, $inclusive = false, $format = 'Y-m-d')
{
    $arr = array();
    $tmp_ts = $from_ts;
    if ($tmp_ts > $to_ts) {
        list($tmp_ts, $to_ts) = array($to_ts, $tmp_ts);
    }
    while (($tmp_ts = strtotime('+1 day', $tmp_ts)) < $to_ts) {
        $arr[] = date($format, $tmp_ts);
    }
    if ($inclusive) {
        array_unshift($arr, date($format, $from_ts));
        $arr[] = date($format, $to_ts);
    }
    return $arr;
}

greedyisg00d

Thanks for your time men hope I do not annoy you...I am currently working on your code and can you include some comments on each line of your code so that I can understand it better on how it works and it will be easier for me to debug it in the future

Also can you give me a sample code on what you meant using between and not between when a specific date is selected. Thanks

Installer

It seems to me that the posted code is simple enough not to need commenting, and that any parts not understood can be made clear by visits to the manual. I subscribe to the "Code Tells You How, Comments Tell You Why" principle, especially for a relatively high-level languange like PHP. "How" or "What" commenting, imo, quickly becomes signal noise. Again, I think the code pretty much documents itself, but if you have any "why" questions, please ask.

The MySQL "BETWEEN" function can be used like this:

$query = "SELECT * FROM my_table WHERE date_field BETWEEN '" . $from_date . "' AND '" . $to_date . "'";

The function compares data inclusively, that is it will return true if either $from_date or $to_date is equal to date_field ("between" is really a misnomer in this usage, but that's another matter). For an exclusive comparison use the "<" and ">" operators, as in my first reply.