Sql 本年度迄今、上一年度迄今和其他

我需要将一组日期分类为“Cur”或“Cur”。年初至今。“年初至今”或“其他”。YTD基于getdate。我有一个用于测试的临时表，它有一个名为“calendar\u date”的DATETIME类型的列。我想出了这个逻辑，它似乎起了作用。我只是想知道，从性能角度来看，这种方法是否有意义，或者其他方法是否更好

select calendar_date,
case when (MONTH(calendar_date) < MONTH(getdate()))
     or (MONTH(calendar_date) = MONTH (getdate())
         AND DAY(calendar_date) <= DAY(getdate())) then
case when YEAR(calendar_date) = YEAR(GETDATE()) then 'CYTD'
when YEAR(calendar_date) = YEAR(getdate()) - 1 then 'LYTD'
else 'Other'
end
else 'Other'
end as Tim_Tag_YTD
from #temp1

---

你的逻辑看起来很好，可以按原样工作

一个稍微简化的替代方案，假设您没有未来的数据

在您的逻辑中，您明确地将未来数据放入“其他”中，您也可以这样做：

select
  calendar_date,
  Tim_Tag_YTD = case when calendar_date > GETDATE() then 'Other' else
                    case DATEDIFF(YEAR, calendar_date, GETDATE())
                    when 0 then 'CYTD'
                    when 1 then 'LYTD'
                    else 'Other'
                    end
                end
from #temp1;

---

有时一些不直观的东西执行得更快。像这样的东西可能值得一试

set variable @FirstOfLastYear to Jan 1 of last year
using sql server date functions

set @FirstOfThisYear = DateAdd(year, 1, @FirstOfLastYear)

select 'last year' period
, whatever else you need
from #temp1 where calendar_date >= @FirstOfLastYear
and calendar_date < @FirstOfThisYear
union
select 'this year' period
, whatever else you need
from #temp1 where calendar_date >= @FirstOfThisYear
and calendar_date < getDate ()
union
select 'other' period
, whatever else you need
from #temp1 where calendar_date <= @FirstOfLastYear
or calendar_date > getdate()

除非你尝试，否则你永远不会知道

set variable @FirstOfLastYear to Jan 1 of last year
using sql server date functions

set @FirstOfThisYear = DateAdd(year, 1, @FirstOfLastYear)

select 'last year' period
, whatever else you need
from #temp1 where calendar_date >= @FirstOfLastYear
and calendar_date < @FirstOfThisYear
union
select 'this year' period
, whatever else you need
from #temp1 where calendar_date >= @FirstOfThisYear
and calendar_date < getDate ()
union
select 'other' period
, whatever else you need
from #temp1 where calendar_date <= @FirstOfLastYear
or calendar_date > getdate()