How to get the week number of the year in php and mysql?

Question

PHP

Hello.
I made a weekly schedule not long ago.
It was necessary to calculate the first week and the final week in the selected period
. I did it like this in PHP

$date_start = strtotime("2018-05-03"); // тут может преобразование отличаться
        $week_start=date("W", $date_start);

That is, we get the 18th week for the date 2018-05-03
We make a request to the database of this type

SELECT `date_invoice` ,WEEK(date_invoice) as week_num FROM `invoce` WHERE `date_invoice` BETWEEN   '2018-05-01' AND '2018-05-31'

And we get 13 records with dates 2018-05-03 and 2018-05-04.
I decided to use the standard WEEK function for the database, as you can see from the query
. But the essence of the problem is that php gives me the date 2018-05-03 - 18 weeks
and MySQL gives the date 2018-05-03 - week 17
But in fact PHP correctly calculates
Here is an example of output from the database, for those who do not believe

Answer 1

try WEEK() to pass second parameter 0 or 1