如何使 row_number () 在 case 子句之后工作？

Question

我在 SQL 服务器上应用此 row_number() 函数时遇到问题。理想情况下，我想使用函数 dense_rank() 但仅在 Oracle 上编写时才有效。

当我运行查询时，我得到 SQL 错误 [207][S0001]：列名称无效 'tag_year'。

    select 
'last 7 days' as time_period,
CAST(dd.CalendarDate as DATE) as 'Date',
dd.CalendarID,
cast(CAST(dd.CalendarDate as DATE) as varchar) as time,
right(CAST(dd.CalendarDate as DATE), 5) as axis_date,
(case
    when dd.CalendarDate between dateadd(month, -11,getdate()) and getdate() then 'cy'
    else 'ly' end) as tag_year,
'DAY' + CAST(
ROW_NUMBER () over (partition by tag_year order by time desc ) as varchar) as time_index, --calendar week day
ROW_NUMBER() over (partition by tag_year order by time desc ) as last_n,
CAST(last_n AS varchar)+time_period as time_key
from dim.Calendar dd
where 
(dd.CalendarDate between getdate() - 7 and getdate() - 1) -- last 31 days
or (dd.CalendarDate between getdate() - 7 - 52 * 7 and getdate() - 1 - 52 * 7);

不确定是什么问题，当我添加分组依据时，它仍然崩溃。

如有任何帮助或指导，我们将不胜感激

Answer 1

tag_year 是在查询中内联创建的表达式的结果。要在另一个表达式上使用它的值，您需要首先将此值创建为子查询中的列。

例如：

select *,
  'DAY' + CAST(
  ROW_NUMBER () over (partition by tag_year order by time desc ) as varchar)
    as time_index, --calendar week day
  ROW_NUMBER() over (partition by tag_year order by time desc ) as last_n,
from (
  select 
    'last 7 days' as time_period,
    CAST(dd.CalendarDate as DATE) as 'Date',
    dd.CalendarID,
    cast(CAST(dd.CalendarDate as DATE) as varchar) as time,
    right(CAST(dd.CalendarDate as DATE), 5) as axis_date,
    case 
      when dd.CalendarDate between dateadd(month, -11,getdate()) and getdate() 
      then 'cy'
      else 'ly'
    end as tag_year,
    CAST(last_n AS varchar)+time_period as time_key
  from dim.Calendar dd
  where 
  (dd.CalendarDate between getdate() - 7 and getdate() - 1) -- last 31 days
  or (dd.CalendarDate between getdate() - 7 - 52 * 7 and getdate() - 1 - 52 * 7)
) x

如何使 row_number () 在 case 子句之后工作？

How do I make row_number () work after a case clause?

sql

row-number

invalid-argument