mysql date comparison with date_format

Question

I googled and tried several ways to compare date but unfortunately didn\'t get the result as expected. I have current state of records like following:

Answer 1

Use 2012-11-02 instead of 02-11-2012 and you will not need date_format() anymore

Answer 2

Your format is fundamentally not a sortable one to start with - you're comparing strings, and the string "28-10-2012" is greater than "02-11-2012".

Instead, you should be comparing dates as dates, and then only converting them into your target format for output.

Try this:

select date_format(date(starttime),'%d-%m-%Y') from data
where date(starttime) >= date '2012-11-02';

(The input must always be in year-month-value form, as per the documentation.)

Note that if starttime is a DATETIME field, you might want to consider changing the query to avoid repeated conversion. (The optimizer may well be smart enough to avoid it, but it's worth checking.)

select date_format(date(starttime),'%d-%m-%Y') from data
where starttime >= '2012-11-02 00:00:00';

(Note that it's unusual to format a date as d-m-Y to start with - it would be better to use y-M-d in general, being the ISO-8601 standard etc. However, the above code does what you asked for in the question.)

Answer 3

Use the following method :

public function dateDiff ($date1, $date2) {
/* Return the number of days between the two dates: */
  return round(abs(strtotime($date1)-strtotime($date2))/86400);
}  
/* end function dateDiff */

It will help!