nested-if - Tableau 自定义日期筛选器

Question

在 Tableau 中，我需要创建一个用作筛选器的字段，因为我需要在表中查看以下 YearMonth：本年本月、本年上月、上年当前月、上年上月

使用以下公式，我没有得到前一年的月份......有什么建议吗？

if datediff("year", [DATE_VALIDATION], today()) =0     /*and [DATE_VALIDATION]< TODAY()*/
and datediff("month", [DATE_VALIDATION], today()) =0   /*and [DATE_VALIDATION]< TODAY()*/
then "Current Year Current Month"

elseif datediff("year", [DATE_VALIDATION], today()) =0 /*and [DATE_VALIDATION]< TODAY()*/
and    datediff("month",[DATE_VALIDATION], today())=1 and [DATE_VALIDATION] < DATEADD("month",-1,TODAY())
then "Current Year Previuous Month"

elseif datediff("year",[DATE_VALIDATION], today())=1 and [DATE_VALIDATION] < DATEADD("year",-1,TODAY())
and     datediff("month", [DATE_VALIDATION], today()) =0 
then "Previuos Year Current Month"

ELSEIF datediff("year",[DATE_VALIDATION], today())=1 and [DATE_VALIDATION] < DATEADD("year",-1,TODAY())
and  datediff("month",[DATE_VALIDATION], today())=1 and [DATE_VALIDATION] < DATEADD("month",-1,TODAY())
then "Previuos Year Previous Month"