JOIN始终是默认值，否则加入匹配值

Question

我有以下SQL Server查询

select r.isactive,r.workingyear,r.startperiod,r.endperiod,r.anniversary
from setup_holiday_policy t cross apply
 (select data
  from dbo.Split(t.scheduleapplication, ',')
 ) di cross apply
 (select max(case when did.id = 1 then did.data end) as isactive,
         max(case when did.id = 2 then did.data end) as workingyear,
         max(case when did.id = 3 then did.data end) as anniversary,
         max(case when did.id = 4 then did.data end) as startperiod,
         max(case when did.id = 5 then did.data end) as endperiod
  from dbo.Split(di.data,':') did
 ) r
 WHERE r.workingyear =  @employeeworkingyears

策略表在workingyear字段中的值可以为0。这意味着当该字段为0时，我应该返回默认记录。

setup_holiday_policy 

因此，如果@employeeworkingyears = 2并且workingyears = 2中有否 setup_holiday_policy，我应该返回工作日字段中具有0值的默认行。

这是返回行的示例。

有任何线索如何实现这一目标？

Answer 1

如果只返回一行（如示例数据所示），您可以使用top执行此操作：

select top 1 r.isactive,r.workingyear,r.startperiod,r.endperiod,r.anniversary
from setup_holiday_policy t cross apply
     (select data
      from dbo.Split(t.scheduleapplication, ',')
     ) di cross apply
     (select max(case when did.id = 1 then did.data end) as isactive,
             max(case when did.id = 2 then did.data end) as workingyear,
             max(case when did.id = 3 then did.data end) as anniversary,
             max(case when did.id = 4 then did.data end) as startperiod,
             max(case when did.id = 5 then did.data end) as endperiod
      from dbo.Split(di.data,':') did
     ) r left outer join
     (select @employeeworkingyears as employeeworkingyears
     ) e
     on 
WHERE r.workingyear in (@employeeworkingyears, 0)
order by r.workingyear desc;