如何编写将电话号码从列转换为单列的 SQL 查询？

如何解决如何编写将电话号码从列转换为单列的 SQL 查询？

如何编写将电话号码从列转换为单列的 SQL 查询。假设有多个 personID，每个 personID 最多有 3 种电话类型，Primary、Secondary 和 Tertiary。目前，对于每个人，他们被列在三个单独的列中。

期望的结果是电话号码都在一列中，另一列有电话类型

当前数据

Person_ID	Primary_Phone	Secondary_Phone	Tertiary_Phone
1	2221111111	5551111111	9991111111
2	2221111112	5551111112	9991111112
3	2221111113	5551111113	9991111113
4	2221111114	5551111114	9991111114

所需数据

Person_ID	电话号码	电话类型
1	2221111111	主要
1	5551111111	中学
1	9991111111	大专
2	2221111112	主要
2	5551111112	中学
2	9991111112	大专
3	2221111113	主要
3	5551111113	中学
3	9991111113	大专
4	2221111114	主要
4	5551111114	中学
4	9991111114	大专

解决方法

在 Oracle 12c 版开始，您可以使用 cross apply 将列反透视为行：

select t.person_id,x.*
from mytable t
cross apply (
    select primary_phone as phone_number,'Primary' as phone_type from dual
    union all select secondary_phone,'Secondary' from dual
    union all select tertiary_phone,'Tiertiary' from dual
) x

在早期版本中，您可以使用 union all:

select person_id,primary_phone as phone_number,'Primary' as phone_type from mytable
union all select person_id,secondary_phone,'Secondary' from mytable
union all select person_id,tertiary_phone,'Tiertiary' from mytable

,

您似乎想做一个unpivot

with p as (
  select 1 person_id,'2221111111' primary_phone,'5551111111' secondary_phone,'9991111111' tertiary_phone
    from dual
  union all
  select 2,'2221111112' primary_phone,'5551111112' secondary_phone,'9991111112' tertiary_phone
    from dual
)
select person_id,phone_number,phone_type
  from p
unpivot (
  phone_number
  for phone_type in (
     primary_phone as 'Primary',secondary_phone as 'Secondary',tertiary_phone as 'Tertiary'
  )
)

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