Based on your criteria (I never really had thought about Thanksgiving
before, as far as when it hits), but here is a small Tcl proc that I
think will do it. You may need to add error checking. Takes the year
(i.e. 2001), and returns the day date (i.e. 22).
-------------------------------------------
proc getTG {year} { set di \[clock format [clock scan $year-11-30] -format "%w"] return [expr {30 -
((($di+1)%7)+2)}]
}
---------------------------------------------
I think this will do it (It might not work for esoteric cases...I didn't
check all). Sorry, I don't know SQL well enough to give an answer in
SQL...maybe someone else will though...or maybe you can extrapolate this
proc into SQL.
I think you may be able to modify this for Memorial and Labor day as
well.
--brett
Josh Berkus wrote:
>
> Folks,
>
> I'm spec'ing a calendar app for PostgreSQL, and was wondering if anyone
> had already solved the following problem:
>
> How can I calculate the dates of American holidays?
>
> Obviously, Christmas & New Year's are easy. As is July 4.
>
> However, Thanksgiving is the last Thursday in November, unless the month
> ends on a Thursday or Friday, in which case it is the next-to-last.
> Memorial Day and Labor Day are simpler, but also use the "First or Last
> Monday in x month" idea.
>
> I was wondering if anyone had already figured out these calculations, in
> any language (SQL would be terrific).
>
> Thanks!
>
> -Josh
>
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