SELECT

    COALESCE(

        (SELECT data_column

         FROM your_table

         WHERE CAST(your_date_column AS DATE) = CAST(DATEADD(yy, DATEDIFF(yy, 0, GETDATE()), 0) AS DATE)  -- 当年第一天

        ), 0) -

    COALESCE(

        (SELECT data_column

         FROM your_table

         WHERE CAST(your_date_column AS DATE) = CAST(DATEADD(yy, DATEDIFF(yy, -1, GETDATE()), -1) AS DATE)  -- 当年最后一天

        ), 0) AS difference

with t1 as (

  select cast('20240101 00:00:00' as datetime) as fdate,56 as fnum

union all

select cast('20241231 00:00:00' as datetime) as fdate,36 as fnum

union all

select cast('20240221 00:00:00' as datetime) as fdate,68 as fnum

union all

select cast('20240518 00:00:00' as datetime) as fdate,19 as fnum

union all

select cast('20240815 00:00:00' as datetime) as fdate,82 as fnum

union all

select cast('20240423 00:00:00' as datetime) as fdate,73 as fnum)

select

  --当年最后一天零点

  sum(case when fdate=dateadd(year,datediff(year,0,dateadd(year,1,getdate())),-1) and fnum is not null then fnum else 0 end) -

--当年第一天零点

  sum(case when fdate=dateadd(yy,datediff(yy,0,getdate()),0) and fnum is not null then fnum else 0 end) as fcz

from t1