查找日期间隔中的所有星期五（下一个星期五递增）

Question

For an x (@startDate) and y (@endDate) interval of date. I want to be able to increment on the next Friday until @endDate.

Pseudo-code init currentDate to startDate

Loop until endDate

set currentDate to next Friday

end loop

I tried this:

set datefirst 5 /* Friday */
CASE
WHEN DATEPART(cdw, @currentDate) = @@datefirst THEN DATEADD(dd, 7, @currentDate)
ELSE DATEADD(dd, ( @@datefirst + ( DATEPART(cdw,@currentDate) ) ) % 7, @currentDate)
END

It doesn't work...

Answer 1

DATEADD(dd,(CASE DATEPART(cdw, @currentDate) WHEN 5 THEN 7 ELSE 5 - DATEPART(cdw,@currentDate) END),@currentDate)