date - 获取 Marklogic 中选定日期的第一天和最后一天日期

Question

我正在尝试使用 MarkLogic 获取任何选定日期的第一天和最后一天日期。
示例:

let $date := xs:date("2018-08-24")      
let $firstDay := "*Should be 1st day of month - of $date*"  
let $lastDay := "*Should be last day of month - of $date*"  
return ("$firstDay:",$firstDay,"$lastDay:",$lastDay)

预计输出日期:

• $firstDay:2018-08-01
• $lastDay:2018-08-31

我可以使用 functx:first-day-of-month($date) 来获取此日期 functx:last-day-of-month($date) 但我想知道 MarkLogic 是否提供任何 API 或替代选项

Answer 1

您可以使用标准 XQuery 直接计算此值 duration arithmetic :

let $date := xs:date("2018-08-24")

let $one-day := xs:dayTimeDuration('P1D')
let $one-month := xs:yearMonthDuration('P1M')
(: subtract days to get to the 1st of the month :)
let $firstDay := $date - (fn:day-from-date($date) - 1) * $one-day
(: get the 1st of the next month and then subtract one day :)
let $lastDay  := $firstDay + $one-month - $one-day

return ("$firstDay:",$firstDay,"$lastDay:",$lastDay)