Question

我知道如果case语句找到该记录的任何第一个匹配项，它将不会检查该记录的其余条件（在我的案例记录2中）。

我也试过UNION，这给了我正确的结果，但有一些额外的记录。任何方法都可以帮我。

create table #temp (Name varchar(100), ColA int, ColB int, ColC int, ColD int)

insert into #temp (name, ColA,ColB, ColC, ColD)
values ('Name1', 1, null, null, null)
      ,('Name2', 1, 1   , null, null)


select name,
case 
    when ColA = 1 then 'some value'
    when ColB = 1 then 'Other value'
    when ColC = 1 then 'some2 value'
    when ColD = 1 then 'some3 value'
end CaseValues
from #temp

select * from #temp


/*when you run this case statement I get only two record. But I need three records for each value matched as below:

    Name    CaseValues

1   Name1   Some value
2   Name2   some vaule
3   Name2   other value
*/

Answer 1

select name, 'some value'
  from from #temp
 where ColA = 1 
union 
select name, 'Other value'
  from #temp
 where ColB = 1
union 
...

Answer 2

喜欢这个吗？

select name, 'some value' from #temp where colA is not null 
union all
select name, 'Other value' from #temp where colB is not null
union all
select name, 'some2 value' from #temp where colC is not null
union all
select name, 'some3 value' from #temp where colD is not null

在案例值匹配时，需要从头开始创建新记录

2 个答案: