PHP MySQL Count every day between DatePeriod - php

Question

I have a DatePeriod
$start = new DateTime('2016-03-01');
$end = new DateTime('2016-03-01 + 1 month');
$period = new DatePeriod($start, new DateInterval('P1D'), $end);
and a SQL Table with workdates:
Now i need a SQL Query to Count every day in the table between the Dateperiod by tagnr (daynumber)
The following code doesn't work for me.
SELECT
COUNT(tagnr) AS totalsumme
FROM
arbeitszeiten
WHERE
tagnr IN ($period)

Answer 1

If you are trying to count the number of dates in the table that are contained in the php date period specified, then the only insurmountable problem I see is that your posted data doesn't contain actual dates. In particular tagnr appears to be the number day of the week (Mon-Sun : 1-7).
Let's presume for a minute your table data does contain actual dates as such:
id tag tagnr ddate
1 Montag 1 2016-03-07
2 Dienstag 2 2016-03-08
3 Mittwoche 3 2016-03-09
4 Donnerstag 4 2016-03-10
5 Freitag 5 2016-03-11
Then the task isn't too difficult to build a sql query using the dates in the range:
<?php
$start = new DateTime('2016-03-01');
$end = new DateTime('2016-03-01 + 1 month');
$period = new DatePeriod($start, new DateInterval('P1D'), $end);
$date_range = "";
// iterate through date range and build up sql string
foreach($period as $date){
// append each date, comma delimited
$date_range .= "'" . $date->format("Y-m-d") . "',";
}
// trim trailing comma
$date_range = rtrim($date_range,",");
$sql = "
SELECT
COUNT(tagnr) AS totalsumme
FROM
arbeitszeiten
WHERE
ddate IN ($date_range)
";
// execute $sql with mysqli, PDO, etc.

Answer 2

Curiously, since your table only shows exactly 5 typical working days, then I wonder if your intention is to actually count how many working days (from the table) exist in the php date interval you've specified. In which case, you can use the php date format after translating from German. Moreover, unless your work days of the week are changing, then it doesn't make sense to hit a database for that info, so you should just hard code it in an array. If they are changing, then you will also need the actual dates for context per my other answer. But, to find the number of working days in the specified php date range, the following code will do this:
<?php
$working_days = array(
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday"
);
$start = new DateTime('2016-03-01');
$end = new DateTime('2016-03-01 + 1 month');
$period = new DatePeriod($start, new DateInterval('P1D'), $end);
$count_of_working_days = 0;
// iterate through date range and count each instance
foreach($period as $date){
// get the day of the week from the date
$day_of_week = $date->format('l');
// check if it's one of the working days
if (in_array($day_of_week,$working_days))
$count_of_working_days++;
}
echo $count_of_working_days;
Output:
23