Question

我有三个CASE陈述：

create view J as 
select *,
  (CASE WHEN A in ('01', ‘03') then TRUE ELSE FALSE END) as X,
  (CASE WHEN A = ‘2' then TRUE ELSE FALSE END) as Y,
  (CASE WHEN A in ('02', '03') then TRUE ELSE FALSE END) as Z
from 
K;

我希望能够创建一个包含X，Y，Z作为值的字段。我尝试了以下方法，但是创建CASE语句的方式只强制第一个参数为true。我理解这是因为值为'03'的观察可以在X或Z中。同样，观察可以在Y或Z中。

create view J as 
(select *,
(CASE
WHEN X = TRUE then 1
WHEN Y = TRUE then 2
WHEN Z = TRUE then 3
ELSE NULL END)
as grouped_field 
from select 
  (CASE WHEN A in ('01', ‘03') then TRUE ELSE FALSE END) as X,
  (CASE WHEN A = ‘2' then TRUE ELSE FALSE END) as Y,
  (CASE WHEN A in ('02', '03') then TRUE ELSE FALSE END) as Z

from 
K));

Answer 1

这样做你想要的吗？

concat((case when X = TRUE then '1' else '0' end),
       (case when Y = TRUE then '1' else '0' end),
       (case when Z = TRUE then '1' else '0' end)
      )

串联运算符在数据库之间有所不同，但通常是||或+。

Answer 2

也许是这样的

select *,
  (CASE WHEN A in ('01', '03') then 'X' ELSE '' END) +   
 ','+ (CASE WHEN A = '2' then 'Y' ELSE '' END) +  
 ','+ (CASE WHEN A in ('02', '03') then 'Z' ELSE '' END) as Field
from 
K;

非互斥独家CASE声明

2 个答案: