使用 UNION 子句时增加一列

Question

我有以下查询：

select row_number() over (order by 1) as id,"-1" AS StatusCode,"Not informed" AS StatusLibelle
union
select row_number() over (order by 1) as id,"0" AS StatusCode,"Off" AS StatusLibelle
union
select row_number() over (order by 1) as id,"1" AS StatusCode,"On" AS StatusLibelle

当我尝试在 hive 上查询它时，我得到以下结果

id StatusCode StatusLibelle
1  -1         Not informed
1   0         Off
1   1         On

这是我的预期输出，id 列应该递增：

id StatusCosqlde StatusLibelle
1  -1         Not informed
2   0         Off
3   1         On

Answer 1

尝试以下操作：

select row_number() over (order by 1) as id,"-1" AS StatusCode,"Not informed" AS StatusLibelle
union
select row_number() over (order by 1) + 1 as id,"0" AS StatusCode,"Off" AS StatusLibelle
union
select row_number() over (order by 1) + 2 as id,"1" AS StatusCode,"On" AS StatusLibelle

Answer 2

为什么要使用 row_number()？

select 1 as id, -1 AS StatusCode, 'Not informed' AS StatusLibelle
union all
select 2 as id, 0 AS StatusCode, 'Off' AS StatusLibelle
union all
select 3 as id, 1 AS StatusCode, 'On' AS StatusLibelle

此外，没有理由使用 UNION，这会产生删除重复项的开销。而且，StatusCode 看起来像一个数字，所以 return 它是一个数字，而不是字符串。

使用 UNION 子句时增加一列

Increment a column when using a UNION clause

sql

hive