sql - performing datetime related operations in PHP

Question

How do you actually perform datetime operations such as adding date, finding difference, find out how many days excluding weekends in an interval? I personally started to pass some of these operations to my postgresql dbms as typically I would only need to issue one sql statement to obtain an answer, however, to do it in PHP way I would have to write a lot more code that means more chances for errors to occur...

Are there any libraries in PHP that does datetime operation in a way that don't require a lot of code? that beats sql in a situation where 'Given two dates, how many workdays are there between the two dates? Implement in either SQL, or $pet_lang' that is solved by making this query?

SELECT  COUNT(*) AS total_days
FROM    (SELECT date '2008-8-26' + generate_series(0,
          (date '2008-9-1' - date '2008-8-26')) AS all_days) AS calendar
WHERE   EXTRACT(isodow FROM all_days) < 6;

Answer 1

While for most datetime operations I would normally convert to Unixtime and perform addition subtraction etc. on the Unixtime integer, you may want to look at the Zend framework Zend_Date class.

This has a lot of the functionality you describe. Although Zend is billed as a "framework" it works exceptionally well as a class library to pick and chose elements from. We routinely include it in projects and then just pull in bits as and when we need them.