Google cloud platform 正在取消BigQuery中可能包含null元素的列的测试

查询生成的结果

查询生成的结果

这个结果的问题是：对于num=6，我没有嵌套列， 因此，当我取消嵌套列时，它会完全删除num=6的行，这将在我要计算发生的总成本时产生差异

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感谢您的帮助

使用

左连接

而不是

，

（这是

交叉连接

的缩写）：

---

使用

左连接

代替

，

（这是

交叉连接

的缩写）：

with a1 as (
  select 1 as num,
    [1,2] as nested,
    2 as cost
),
a2 as (
  select 2 as num,
  [4,7] as nested,
  2 as cost
),
a3 as (
  select 3 as num,
  [9,8] as nested,
  2 as cost
),
a4 as (
  select 4 as num,
  [4, 6, 8] as nested,
  2 as cost
),
a5 as (
  select 5 as num,
  [19, 11] as nested,
  2 as cost
),
a6 as (
  select 6 as num,
  [] as nested,
  2 as cost
),
table as(
 select * from a1
 union all
 select * from a2
  union all
 select * from a3
  union all
 select * from a4
  union all
 select * from a5
  union all
 select * from a6
) 
select * except(nested)
from table, unnest(nested) as unnested

select num, count(unnested) as count, max(cost) as cost_incurred
from table, unnest(nested) as unnested
group by num

select * except(nested)
from table left join unnest(nested) as unnested

select num, count(unnested) as count, max(cost) as cost_incurred
from table left join unnest(nested) as unnested
group by num