在PB中计算指定日期相对数量单位前(后)的日期

通过灵活使用PB提供的RelativeDate函数还是比较容易实现的，RelativeDate函数要求提供的第一个参数必须为date类型，也即该函数只能处理日期 （不包含时间）运算，因此有关时间部分的运算只能分开执行。以下是f_dateadd函数完整代码，在PB8/9上测试通过。 /******************************************************************* 函数名称：f_dateadd() 参数说明:as_datepart string 日期单位,可取如下值: year,yyyy,yy,y,年:年; quarter,qq,季:季; month,mm,m,月:月; day,dd,天:天; week,wk,ww,星期,周:星期; hour,hh,h,小时:小时 minute,mi,分:分钟; second,ss,秒:秒; millisecond,ms,毫秒:毫秒 al_number long 相对数量,取后来日期,为正值, 取前置日期,为负值 adt_refdate datetime 参考日期 返回值： datetime 相对数量单位前(后)的日期 若三个参数中有一个为空,则返回空值,若输入的日期单位非要求的单位也返回空值 功能描述：计算指定日期相对数量单位前(后)的日期 创建日期：2006-07-27 版本号： V1.0 *******************************************************************/ datetime ldt_return string ls_sql any la_values[] long ll_year,ll_month,ll_day,ll_hour,ll_minute,ll_second,ll_millisecond long ll_day_tmp,ll_hour_tmp,ll_minute_tmp,ll_second_tmp,ll_millisecond_tmp date ld_return time lt_return //检查参数是否有效 if isnull(as_datepart) or isnull(al_number) or isnull(adt_refdate) then setnull(ldt_return) return ldt_return end if if al_number = 0 then return adt_refdate //取各部分时间 ll_year = year(date(adt_refdate)) ll_month = month(date(adt_refdate)) ll_day = day(date(adt_refdate)) ll_hour = hour(time(adt_refdate)) ll_minute = minute(time(adt_refdate)) ll_second = second(time(adt_refdate)) ll_millisecond = long(rightw(string(adt_refdate,'yyyy-mm-dd hh:mm:ss.fff'),3)) //根据不同的日期单位进行计算 choose case lower(as_datepart) case "year","yyyy","yy","y","年"//年 ll_year = ll_year + al_number if not isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) then do while isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) ll_day -- loop end if ld_return = date(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "quarter","qq","q","季"//季 ll_year = ll_year + long((al_number * 3 + ll_month) / 12) - 1 if mod(al_number * 3 + ll_month,12) = 0 then ll_month = 12 else ll_month = mod(al_number * 3 + ll_month,12) end if                    if not isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) then do while isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) ll_day -- loop end if ld_return = date(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "month","mm","m","月"//月 if al_number > 0 then ll_year = ll_year + al_number / 12 else if mod(abs(al_number),12) = 0 then ll_year = ll_year + al_number / 12 else ll_year = ll_year + al_number / 12 + 1 end if end if ll_month = ll_month + mod(al_number,12) if ll_month > 12 then ll_year = ll_year + 1 ll_month = ll_month - 12 elseif ll_month = 0 then ll_year = ll_year - 1 ll_month = 12                  end if      if not isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) then do while isdate(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) ll_day -- loop end if      ld_return = date(string(ll_year) + "-" + string(ll_month) + "-" + string(ll_day)) lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "day","dd","d","日"//日 ld_return = relativedate (date(adt_refdate),al_number) lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "week","wk","ww","星期","周"//周 return f_dateadd('day',al_number * 7,adt_refdate) case "hour","hh","h","小时"//小时 ld_return = relativedate (date(adt_refdate),truncate((al_number + ll_hour) / 24,0))            if al_number > 0 then ll_hour = mod(al_number + ll_hour,24) else ll_hour = 24 - mod(abs(al_number + ll_hour),24) ld_return = relativedate (ld_return,-1) end if lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "minute","mi","n","分"//分钟 if ll_hour * 60 + ll_minute + al_number < 0 then ll_day_tmp = ceiling(abs(ll_hour * 60 + ll_minute + al_number) / 60 / 24) * (-1) else ll_day_tmp = (ll_hour * 60 + ll_minute + al_number) / 60 / 24 end if ld_return = relativedate (date(adt_refdate),ll_day_tmp) ll_hour_tmp = (ll_hour * 60 + ll_minute + al_number - ll_day_tmp * 24 * 60) / 60 ll_minute = ((ll_hour * 60 + ll_minute + al_number - ll_day_tmp * 24 * 60) / 60 - ll_hour_tmp) * 60 ll_hour = ll_hour_tmp lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "second","ss","s","秒"//秒 if ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number < 0 then ll_day_tmp = ceiling(abs(ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number) / 60 / 60 / 24) * (-1) else ll_day_tmp = (ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number) / 60 / 60 / 24 end if ld_return = relativedate (date(adt_refdate),ll_day_tmp) ll_hour_tmp = (ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number - ll_day_tmp * 24 * 60 * 60) / 60 / 60 ll_minute_tmp = (ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number - ll_day_tmp * 24 * 60 * 60 - ll_hour_tmp * 60 * 60) / 60 ll_second = ll_hour * 60 * 60 + ll_minute * 60 + ll_second + al_number - ll_day_tmp * 24 * 60 * 60 - ll_hour_tmp * 60 * 60 - ll_minute_tmp * 60 ll_hour = ll_hour_tmp ll_minute = ll_minute_tmp lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case "millisecond","ms","毫秒"//毫秒 //先换算成秒计算 if ll_millisecond + al_number < 0 then ll_second_tmp = ceiling(abs(ll_millisecond + al_number) / 1000) * (-1) else ll_second_tmp = (ll_millisecond + al_number) / 1000 end if ll_millisecond = ll_millisecond + al_number - ll_second_tmp * 1000 if ll_millisecond >= 1000 then ll_second_tmp = ll_second_tmp + 1 ldt_return = f_dateadd('second',ll_second_tmp,adt_refdate) ll_millisecond = 1000 - ll_millisecond else ldt_return = f_dateadd('second',ll_second_tmp,adt_refdate) end if ld_return = date(ldt_return) ll_hour = hour(time(ldt_return)) ll_minute = minute(time(ldt_return)) ll_second = second(time(ldt_return)) lt_return = time(string(ll_hour,'00')+":"+string(ll_minute,'00')+":"+string(ll_second,'00')+"."+string(ll_millisecond,'000')) case else//无效参数 setnull(ldt_return) return ldt_return end choose ldt_return = datetime(ld_return,lt_return) return ldt_return

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