January 2018 Archives

Simple (Date) Range Overlap Detection

I started down this particular rabbit hole when (a) I had to check for date range overlaps when worrying about scheduling appraisals; and (b) my attempts to use SQL BETWEEN resulted in complicated, hard-to-read SQL.

Now you would think that BETWEEN should give you easy-to-understand SQL for date ranges. Maybe in the hands of others BETWEEN does, but for me by the time I accounted for all of the cases the BETWEEN-based SQL date range overlap detection got more complicated than I thought it needed to be. So I drew up some diagrams, which eventually led me to the realization that this:…

Stack Overflow Considered as a Grimoire or Trove

Back in the day, when I came upon a particularly juicy tip/hint/trick/kludge/etc. I would write it down somewhere (way back -- in a paper notebook; more recently, somewhere like TiddlyWiki). But I don't do that anymore -- why?

The answer is Stack Overflow. When I have a question, a web search often has 1 or more Stack Overflow answers at the top - answers that usually help me fix (or work around) the problem I have. It really is impressive how often Stack Overflow has just the answer I need and in just enough detail. (Disclosure: I answer questions on Stack Overflow on a semi-regular …

About Mark Leighton Fisher

user-pic Perl/CPAN user since 1992.