寻找月度间隔
我的工作意味着我必须从特定的date计算6到18个月。 我有2个例子。 示例1：我的工作要求我计算客户的退款。 这些退款一次只能使用18个月，退款期限的最后一天是信件发送给客户的那一天。 那么，如果退款信将在2012年8月28日发出，那么这段时间的第一个date是什么？ 另外，如果是8月29日，30日和31日（08/28/2012 – 08/31/2012）。 我的计算表明，所有这些时间段都以2011年3月1日为开始date。 我使用SAS作为程序工具。 这是我使用的function：
eighteen_months = intnx('month',Visit_date,18,'sameday')+1; 我所做的主要假设是1个月，等于第一个月的第一个date，最后一个date和同一个月（2012年1月1日至2012年1月31日）。 随后，3个月等于第一个月的第一个date和第三个月的最后一个date（2012年1月1日至2012年3月31日或2012年4月1日至2012年6月30日）。 以下是其他18个月的计算：
First Date Last Date 10/30/1999 4/29/2001 5/6/2006 11/5/2007 4/30/2012 10/29/2013 4/3/2018 10/2/2019 2/24/2024 8/23/2025 5/10/2026 11/9/2027
这个问题发生在我8月28日至31日的原始案例中，18个月实际上可能有4个不同的时间长度。
例2：我的工作也要求我在第一次约会的时候做相反的事情，并且需要计算出6到18个月的时间。 我最近被问到，如果第一个date是2012年6月22日，6个月是什么？ 我2012年12月21日作出回应，并被告知，这实际上是2012年12月22日。 关于公司如何计算，没有真正的文件/逻辑。 这是我在SAS的function。
Six_months = intnx('month',Visit_date,6,'sameday')-1;
我正在尝试build立一个stream程，并希望看到是否有人在一致的基础上进入这些stream程，并且如果在Excel / SAS中有更简单的方法。 任何答复将不胜感激。
要从Excel中的最后一个date获取第一个date，请在“最后date”在B2中尝试此公式
=EDATE(B2,-18)+1
这适用于您列出的6个示例，也适用于从2012年8月28日/ 29/30/31日起返回2011年3月1日
EDATE函数，如你猜测的那样，可以用来从date中增加或者减去几个月，如果这个月不存在的那一天，比如2月30日，那么它默认为那个月的最后一天
许多数据库支持add_months或dateadd或类似的东西（包括Teradata）。 为了在18个月之前或之后得到date，你可以做如下的事情：
select add_months(LastDate, -18), LastDate
我认为这回答了前面的问题。 答案的问题有点棘手，因为有多个date。 您可以通过以下技巧获得第一个和最后一个date：
select add_months(FirstDate, 18) as LastDate1, add_months(FirstDate+1, 18) - 1 as LastDate2
也就是说，add_months返回与未来18个月的情况相匹配的第一天（我非常确定这一点，但Teradata并非100％正面）。 第二天是第二天18个月前的一天。 通常情况下，它和第一次约会是一样的，但并不总是如此。
这是来自洛林和丹的蛮力之路
%MACRO DATES(YEAR, lib); data post.try&lib.; set post.pact; IF DTE_EFFECTIVE LE &year. LE DTE_END THEN DO ELIGMONTH= &year.; FORMAT ELIGMONTH MMDDYY10.; OUTPUT post.TRY&lib.; END; run; %MEND; %DATES (YEAR='01JAN2000'D, LIB=a) %DATES (YEAR='01FEB2000'D, LIB=b) %DATES (YEAR='01MAR2000'D, LIB=c) %DATES (YEAR='01APR2000'D, LIB=d) %DATES (YEAR='01MAY2000'D, LIB=e) %DATES (YEAR='01JUN2000'D, LIB=f) %DATES (YEAR='01JUL2000'D, LIB=g) %DATES (YEAR='01AUG2000'D, LIB=h) %DATES (YEAR='01SEP2000'D, LIB=i) %DATES (YEAR='01OCT2000'D, LIB=j) %DATES (YEAR='01NOV2000'D, LIB=k) %DATES (YEAR='01DEC2000'D, LIB=l) %DATES (YEAR='01JAN2001'D, LIB=m) %DATES (YEAR='01FEB2001'D, LIB=n) %DATES (YEAR='01MAR2001'D, LIB=o) %DATES (YEAR='01APR2001'D, LIB=p) %DATES (YEAR='01MAY2001'D, LIB=q) %DATES (YEAR='01JUN2001'D, LIB=r) %DATES (YEAR='01JUL2001'D, LIB=s) %DATES (YEAR='01AUG2001'D, LIB=t) %DATES (YEAR='01SEP2001'D, LIB=u) %DATES (YEAR='01OCT2001'D, LIB=v) %DATES (YEAR='01NOV2001'D, LIB=w) %DATES (YEAR='01DEC2001'D, LIB=x) %DATES (YEAR='01JAN2002'D, LIB=y) %DATES (YEAR='01FEB2002'D, LIB=z) %DATES (YEAR='01MAR2002'D, LIB=aa) %DATES (YEAR='01APR2002'D, LIB=bb) %DATES (YEAR='01MAY2002'D, LIB=cc) %DATES (YEAR='01JUN2002'D, LIB=dd) %DATES (YEAR='01JUL2002'D, LIB=ee) %DATES (YEAR='01AUG2002'D, LIB=ff) %DATES (YEAR='01SEP2002'D, LIB=gg) %DATES (YEAR='01OCT2002'D, LIB=hh) %DATES (YEAR='01NOV2002'D, LIB=ii) %DATES (YEAR='01DEC2002'D, LIB=jj) %DATES (YEAR='01JAN2003'D, LIB=kk) %DATES (YEAR='01FEB2003'D, LIB=ll) %DATES (YEAR='01MAR2003'D, LIB=mm) %DATES (YEAR='01APR2003'D, LIB=nn) %DATES (YEAR='01MAY2003'D, LIB=oo) %DATES (YEAR='01JUN2003'D, LIB=pp) %DATES (YEAR='01JUL2003'D, LIB=qq) %DATES (YEAR='01AUG2003'D, LIB=rr) %DATES (YEAR='01SEP2003'D, LIB=ss) %DATES (YEAR='01OCT2003'D, LIB=tt) %DATES (YEAR='01NOV2003'D, LIB=uu) %DATES (YEAR='01DEC2003'D, LIB=vv) %DATES (YEAR='01JAN2004'D, LIB=ww) %DATES (YEAR='01FEB2004'D, LIB=xx) %DATES (YEAR='01MAR2004'D, LIB=yy) %DATES (YEAR='01APR2004'D, LIB=zz) %DATES (YEAR='01MAY2004'D, LIB=aa) %DATES (YEAR='01JUN2004'D, LIB=bb) %DATES (YEAR='01JUL2004'D, LIB=cc) %DATES (YEAR='01AUG2004'D, LIB=dd) %DATES (YEAR='01SEP2004'D, LIB=ee) %DATES (YEAR='01OCT2004'D, LIB=ff) %DATES (YEAR='01NOV2004'D, LIB=gg) %DATES (YEAR='01DEC2004'D, LIB=hh) %DATES (YEAR='01JAN2005'D, LIB=ii) %DATES (YEAR='01FEB2005'D, LIB=jj) %DATES (YEAR='01MAR2005'D, LIB=kk) %DATES (YEAR='01APR2005'D, LIB=ll) %DATES (YEAR='01MAY2005'D, LIB=mm) %DATES (YEAR='01JUN2005'D, LIB=nn) %DATES (YEAR='01JUL2005'D, LIB=oo) %DATES (YEAR='01AUG2005'D, LIB=pp) %DATES (YEAR='01SEP2005'D, LIB=qq) %DATES (YEAR='01OCT2005'D, LIB=rr) %DATES (YEAR='01NOV2005'D, LIB=ss) %DATES (YEAR='01DEC2005'D, LIB=tt) %DATES (YEAR='01JAN2006'D, LIB=uu) %DATES (YEAR='01FEB2006'D, LIB=vv) %DATES (YEAR='01MAR2006'D, LIB=ww) %DATES (YEAR='01APR2006'D, LIB=xx) %DATES (YEAR='01MAY2006'D, LIB=yy) %DATES (YEAR='01JUN2006'D, LIB=zz) %DATES (YEAR='01JUL2006'D, LIB=aaa) %DATES (YEAR='01AUG2006'D, LIB=bbb) %DATES (YEAR='01SEP2006'D, LIB=ccc) %DATES (YEAR='01OCT2006'D, LIB=ddd) %DATES (YEAR='01NOV2006'D, LIB=eee) %DATES (YEAR='01DEC2006'D, LIB=fff) %DATES (YEAR='01JAN2007'D, LIB=ggg) %DATES (YEAR='01FEB2007'D, LIB=hhh) %DATES (YEAR='01MAR2007'D, LIB=iii) %DATES (YEAR='01APR2007'D, LIB=jjj) %DATES (YEAR='01MAY2007'D, LIB=kkk) %DATES (YEAR='01JUN2007'D, LIB=lll) %DATES (YEAR='01JUL2007'D, LIB=mmm) %DATES (YEAR='01AUG2007'D, LIB=nnn) %DATES (YEAR='01SEP2007'D, LIB=ooo) %DATES (YEAR='01OCT2007'D, LIB=ppp) %DATES (YEAR='01NOV2007'D, LIB=qqq) %DATES (YEAR='01DEC2007'D, LIB=rrr) %DATES (YEAR='01JAN2008'D, LIB=sss) %DATES (YEAR='01FEB2008'D, LIB=ttt) %DATES (YEAR='01MAR2008'D, LIB=uuu) %DATES (YEAR='01APR2008'D, LIB=vvv) %DATES (YEAR='01MAY2008'D, LIB=www) %DATES (YEAR='01JUN2008'D, LIB=xxx) %DATES (YEAR='01JUL2008'D, LIB=yyy) %DATES (YEAR='01AUG2008'D, LIB=zzz) %DATES (YEAR='01SEP2008'D, LIB=aaaa) %DATES (YEAR='01OCT2008'D, LIB=bbbb) %DATES (YEAR='01NOV2008'D, LIB=cccc) %DATES (YEAR='01DEC2008'D, LIB=dddd) %DATES (YEAR='01JAN2009'D, LIB=eeee) %DATES (YEAR='01FEB2009'D, LIB=ffff) %DATES (YEAR='01MAR2009'D, LIB=gggg) %DATES (YEAR='01APR2009'D, LIB=hhhh) %DATES (YEAR='01MAY2009'D, LIB=iiii) %DATES (YEAR='01JUN2009'D, LIB=jjjj) %DATES (YEAR='01JUL2009'D, LIB=kkkk) %DATES (YEAR='01AUG2009'D, LIB=llll) %DATES (YEAR='01SEP2009'D, LIB=mmmm) %DATES (YEAR='01OCT2009'D, LIB=nnnn) %DATES (YEAR='01NOV2009'D, LIB=oooo) %DATES (YEAR='01DEC2009'D, LIB=pppp) %DATES (YEAR='01JAN2010'D, LIB=qqqq) %DATES (YEAR='01FEB2010'D, LIB=rrrr) %DATES (YEAR='01MAR2010'D, LIB=ssss) %DATES (YEAR='01APR2010'D, LIB=tttt) %DATES (YEAR='01MAY2010'D, LIB=uuuu) %DATES (YEAR='01JUN2010'D, LIB=vvvv) %DATES (YEAR='01JUL2010'D, LIB=wwww) %DATES (YEAR='01AUG2010'D, LIB=xxxx) %DATES (YEAR='01SEP2010'D, LIB=yyyy) %DATES (YEAR='01OCT2010'D, LIB=zzzz) %DATES (YEAR='01NOV2010'D, LIB=aaaaa) %DATES (YEAR='01DEC2010'D, LIB=bbbbb) %DATES (YEAR='01JAN2011'D, LIB=ccccc) %DATES (YEAR='01FEB2011'D, LIB=ddddd) %DATES (YEAR='01MAR2011'D, LIB=eeeee) %DATES (YEAR='01APR2011'D, LIB=fffff) %DATES (YEAR='01MAY2011'D, LIB=ggggg) %DATES (YEAR='01JUN2011'D, LIB=hhhhh) %DATES (YEAR='01JUL2011'D, LIB=iiiii) %DATES (YEAR='01AUG2011'D, LIB=jjjjj) %DATES (YEAR='01SEP2011'D, LIB=kkkkk) %DATES (YEAR='01OCT2011'D, LIB=lllll) %DATES (YEAR='01NOV2011'D, LIB=mmmmm) %DATES (YEAR='01DEC2011'D, LIB=nnnnn) %DATES (YEAR='01JAN2012'D, LIB=ooooo) %DATES (YEAR='01FEB2012'D, LIB=ppppp) %DATES (YEAR='01MAR2012'D, LIB=qqqqq) %DATES (YEAR='01APR2012'D, LIB=rrrrr) %DATES (YEAR='01MAY2012'D, LIB=sssss) %DATES (YEAR='01JUN2012'D, LIB=ttttt) %DATES (YEAR='01JUL2012'D, LIB=uuuuu) %DATES (YEAR='01AUG2012'D, LIB=vvvvv) %DATES (YEAR='01SEP2012'D, LIB=wwwww) %DATES (YEAR='01OCT2012'D, LIB=xxxxx) %DATES (YEAR='01NOV2012'D, LIB=yyyyy) %DATES (YEAR='01DEC2012'D, LIB=zzzzz) %DATES (YEAR='01JAN2013'D, LIB=aaaaaa) %DATES (YEAR='01FEB2013'D, LIB=bbbbbb) %DATES (YEAR='01MAR2013'D, LIB=cccccc) %DATES (YEAR='01APR2013'D, LIB=dddddd) %DATES (YEAR='01MAY2013'D, LIB=eeeeee) %DATES (YEAR='01JUN2013'D, LIB=ffffff) %DATES (YEAR='01JUL2013'D, LIB=gggggg) %DATES (YEAR='01AUG2013'D, LIB=hhhhhh) %DATES (YEAR='01SEP2013'D, LIB=iiiiii) %DATES (YEAR='01OCT2013'D, LIB=jjjjjj) %DATES (YEAR='01NOV2013'D, LIB=kkkkkk) %DATES (YEAR='01DEC2013'D, LIB=llllll) data post.final; set post.TRYa post.TRYb post.TRYc post.TRYd post.TRYe post.TRYf post.TRYg post.TRYh post.TRYi post.TRYj post.TRYk post.TRYl post.TRYm post.TRYn post.TRYo post.TRYp post.TRYq post.TRYr post.TRYs post.TRYt post.TRYu post.TRYv post.TRYw post.TRYx post.TRYy post.TRYz post.TRYaa post.TRYbb post.TRYcc post.TRYdd post.TRYee post.TRYff post.TRYgg post.TRYhh post.TRYii post.TRYjj post.TRYkk post.TRYll post.TRYmm post.TRYnn post.TRYoo post.TRYpp post.TRYqq post.TRYrr post.TRYss post.TRYtt post.TRYuu post.TRYvv post.TRYww post.TRYxx post.TRYyy post.TRYzz post.TRYaa post.TRYbb post.TRYcc post.TRYdd post.TRYee post.TRYff post.TRYgg post.TRYhh post.TRYii post.TRYjj post.TRYkk post.TRYll post.TRYmm post.TRYnn post.TRYoo post.TRYpp post.TRYqq post.TRYrr post.TRYss post.TRYtt post.TRYuu post.TRYvv post.TRYww post.TRYxx post.TRYyy post.TRYzz post.TRYaaa post.TRYbbb post.TRYccc post.TRYddd post.TRYeee post.TRYfff post.TRYggg post.TRYhhh post.TRYiii post.TRYjjj post.TRYkkk post.TRYlll post.TRYmmm post.TRYnnn post.TRYooo post.TRYppp post.TRYqqq post.TRYrrr post.TRYsss post.TRYttt post.TRYuuu post.TRYvvv post.TRYwww post.TRYxxx post.TRYyyy post.TRYzzz post.TRYaaaa post.TRYbbbb post.TRYcccc post.TRYdddd post.TRYeeee post.TRYffff post.TRYgggg post.TRYhhhh post.TRYiiii post.TRYjjjj post.TRYkkkk post.TRYllll post.TRYmmmm post.TRYnnnn post.TRYoooo post.TRYpppp post.TRYqqqq post.TRYrrrr post.TRYssss post.TRYtttt post.TRYuuuu post.TRYvvvv post.TRYwwww post.TRYxxxx post.TRYyyyy post.TRYzzzz post.TRYaaaaa post.TRYbbbbb post.TRYccccc post.TRYddddd post.TRYeeeee post.TRYfffff post.TRYggggg post.TRYhhhhh post.TRYiiiii post.TRYjjjjj post.TRYkkkkk post.TRYlllll post.TRYmmmmm post.TRYnnnnn post.TRYooooo post.TRYppppp post.TRYqqqqq post.TRYrrrrr post.TRYsssss post.TRYttttt post.TRYuuuuu post.TRYvvvvv post.TRYwwwww post.TRYxxxxx post.TRYyyyyy post.TRYzzzzz post.TRYaaaaaa post.TRYbbbbbb post.TRYcccccc post.TRYdddddd post.TRYeeeeee post.TRYffffff post.TRYgggggg post.TRYhhhhhh post.TRYiiiiii post.TRYjjjjjj post.TRYkkkkkk post.TRYllllll ;run;