Possible Duplicate:
PHP, see if date range is partly within another date range
I have 2 dates, a start date (2011-01-01) and an end date (2011-02-28).
I have a third date that starts on 2010-01-01 and ends on 2012-03-01. This means that this third date falls within the first 2 dates range.
If the third dates start and/or end date is not within the 2 dates then it must be false.
How can I check this using php?