除了 case when 之外的其他解决方案

Question

我有一个 firebird 数据库和这个查询：

select distinct
 case
  when exists (select * from fixvar
               where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to) and costcenter_id=10)
  then (select fix from fixvar where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to) and costcenter_id=10)
  else (select fix from fixvar where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to))
 end as fix,
 case
  when exists (select * from fixvar
               where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to) and costcenter_id=10)
  then (select var from fixvar where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to) and costcenter_id=10)
  else (select var from fixvar where costtype_id=7 and extract(year from ct_from)<=2017 and
               2017<=extract(year from ct_to) and costcenter_id=10)
 end as var
from fixvar

我得到了正确的结果，但我可以缩短它吗？

我想要的：我想查询字段fix和var。如果有一行 costcenter_id 是 10，那么我想要相应的 fix 和 var 值，如果没有，那么我们没有的值不是 costcenter_id (-1).

编辑：

示例数据：

如您所见，有两行。因此，如果 costcenter_id=10 存在一行，那么我想要 appr。 fix 和 var 值，如果没有包含此 costcenter_id 的行，那么我想要 fix 和 var 值，其中 costcenter_id=-1 .

Answer 1

我想，我有解决办法：

select
 first 1 fix, var, costcenter_id
from 
 fixvar
where
 costtype_id=7 
and 
 2017 between extract(year from ct_from) and extract(year from ct_to)
and
 costcenter_id in (-1, 10)
order by costcenter_id desc

除了 case when 之外的其他解决方案

other solution than case when

sql

case-when