我无法通过sum函数使此查询工作

Question

此查询给出一个错误：

select ep, 
  case
    when ob is null and b2b_ob is null then 'a'
    when ob is not null or b2b_ob is not null then 'b'
    else null
  end as type,
  sum(b2b_d + b2b_t - b2b_i) as sales
from table
where ...
group by ep, type

错误：ORA-00904：“类型”：无效标识符

当我与 group by ep, ，错误消息变为：

ORA-00979：不是通过表达的组

如果我删除行，则整个查询正常 sum(b2b_d+b2b_t-b2b_i) as sales 和 group by ..., ，因此问题应与按功能进行的总和和组有关。我该如何做这项工作？在此先感谢您的帮助。

Answer 1

不幸的是，SQL不允许您按子句中的组中的列别名，因此您要么必须重复此类案例：

select ep, 
  case
    when ob is null and b2b_ob is null then 'a'
    when ob is not null or b2b_ob is not null then 'b'
    else null
  end as type,
  sum(b2b_d + b2b_t - b2b_i) as sales
from table
where ...
group by ep,
  case
    when ob is null and b2b_ob is null then 'a'
    when ob is not null or b2b_ob is not null then 'b'
    else null
  end

或使用这样的在线视图：

select ep, 
  type,
  sum(b2b_d + b2b_t - b2b_i) as sales
from
( select ep, 
    case
      when ob is null and b2b_ob is null then 'a'
      when ob is not null or b2b_ob is not null then 'b'
      else null
    end as type,
    b2b_d,
    b2b_t,
    b2b_i
  from table
  where ...
)
group by ep, type