Crystal Reports XI 中正确的 ISO 周编号

如何在 Crystal Reports XI 中获取给定日期的 ISO-8601 周数？

水晶报表支持DatePart- 可以为您提供给定日期的 ISO 周数的函数。

NumberVar week := DatePart("ww", date, crMonday, crFirstFourDays);

然而，在 Crystal Reports XI 中存在一个错误，会在新年期间给出错误的结果。最好的解决方案可能是创建一个自己的函数 getISOWeekNumber：

Function (optional DateVar d := CurrentDate)
NumberVar week := DatePart("ww", d, crMonday, crFirstFourDays);

// Correct for that CR doesn't handle the fact that the last days of a year can belong to week 1 of the next year:
if week = 53 and DatePart("ww", cDate(year(d) + 1, 1, 1), crMonday, crFirstFourDays) = 1 then
    week := 1

// A bug in CR makes DatePart return values like 9363 for days in January that belongs to the last week of the previous year.
else if week > 53 then
    week := DatePart("ww", cDate(year(d) - 1, 12, 31), crMonday, crFirstFourDays);

week;

要获取特定日期的“周年”，您可以使用以下函数：

// Returns the year to which the ISO week of the specified date belongs.
// E.g. 2012-12-31 will return 2013, as that date belongs to week 1 of 2013.
Function (optional DateVar d := CurrentDate)

NumberVar week := getISOWeekNumber (d);

if week = 1 and month(d) = 12 then
    year(d) + 1
else if week > 10 and month(d) = 1 then
    year(d) - 1
else
    year(d);