在Crystal Reports XI中正確的ISO星期編號

Question

如何在Crystal Reports XI中獲取給定日期的ISO-8601星期編號？

Answer 1

Crystal Reports支持DatePart-功能，它可以爲您提供給定日期的ISO周編號。

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

但是，在Crystal Reports XI中存在一個錯誤，導致在新的一年發生錯誤的結果。最好的解決辦法可能是創建一個自己的功能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; 

獲取特定日期的「一週年」，那麼你可以使用下面的功能：

// 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);