如何编写一个 SQL 查询，将 phone 数字从列转换为单个列？

Question

如何编写一个 SQL 查询，将 phone 个数字从列转换为单个列。假设有多个 personID，每个 personID 最多有 3 phone 种类型，Primary、Secondary 和 Tertiary。目前，对于每个人，他们都列在三个单独的列中。

期望的结果是 phone 个数字都在一列中，而另一列有 phone 个类型

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	Phone_Number	Phone_Type
1	2221111111	Primary
1	5551111111	Secondary
1	9991111111	Tertiary
2	2221111112	Primary
2	5551111112	Secondary
2	9991111112	Tertiary
3	2221111113	Primary
3	5551111113	Secondary
3	9991111113	Tertiary
4	2221111114	Primary
4	5551111114	Secondary
4	9991111114	Tertiary

Answer 1

在 Oracle 起始版本 12c 中，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

Answer 2

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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如何编写一个 SQL 查询，将 phone 数字从列转换为单个列？

How do write an SQL query that transforms phone numbers from columns into a single column?

sql

oracle

union

unpivot

lateral-join