我希望能够在同一个表中克隆记录及其后代。我的表格的一个示例如下:
表1
id | parentid | name
---------------------
1 | 0 | 'Food'
2 | 1 | 'Taste'
3 | 1 | 'Price'
4 | 2 | 'Taste Requirements'
“id”列是主键并且自动增量。 “食物”记录(即 id = 1)下面有两个记录,称为“口味”和“价格”。 “品味”记录下面有一个名为“品味要求”的记录。我希望能够克隆“Food”记录,以便 Table1 如下所示:
表1
id | parentid | name
---------------------
1 | 0 | 'Food'
2 | 1 | 'Taste'
3 | 1 | 'Price'
4 | 2 | 'Taste Requirements'
5 | 0 | 'Cookies'
6 | 5 | 'Taste'
7 | 5 | 'Price'
8 | 6 | 'Taste Requirements'
(其中“Cookies”是我要创建的新类别的名称)。我可以使用以下方法选择“Food”的所有后代:
with Table1_CTE( id, parentid, name )
as
(
select t.id, t.parentid, t.name from Table1 t
where t.id = 1
union all
select t.id, t.parentid,t. name from Table1 t
inner join Table1_CTE as tc
on t.parentid = tc.id
)
select id, parentid, name from Table1_CTE
我可以使用以下方法克隆“食物”记录(即 id = 1):
insert into Table1 ( parentid, name )
select ( parentid, 'Cookies' )
from Table1 where id = 1
但我在尝试组合两个查询来克隆“Food”的后代时遇到问题。另外,我试图避免使用存储过程、触发器、curosrs 等。我想要做的事情可能吗?我在网上看到了一些示例,但无法将它们应用到我的要求。
最佳答案
正如 Martin 建议的那样,您需要启用 IDENTITY_INSERT
以便可以推送自己的身份值。您可能还需要获取表锁以确保 Max( Id ) 返回正确的值。
If object_id('tempdb..#TestData') is not null
Drop Table #TestData
GO
Create Table #TestData
(
Id int not null identity(1,1) Primary Key
, ParentId int not null
, Name varchar(50) not null
)
GO
Set Identity_Insert #TestData On
GO
Insert #TestData( Id, ParentId, Name )
Values( 1,0,'Food' )
, ( 2,1,'Taste' )
, ( 3,1,'Price' )
, ( 4,2,'Taste Requirement' );
With Data As
(
Select Cast(MaxId.Id + 1 As int) As Id
, T.ParentId
, 'Copy Of ' + T.name As Name
, T.Id As OldId
, 0 As OldParentId
From #TestData As T
Cross Join( Select Max( id ) As Id From #TestData ) As MaxId
Where T.Name = 'Food'
Union All
Select Cast(Parent.id + Row_Number() Over( Order By Child.Id ) + 1 As int)
, Parent.Id
, 'Copy of ' + Child.Name
, Child.Id
, Child.ParentId
From Data As Parent
Join #TestData As Child
On Child.ParentId = Parent.OldId
)
Insert #TestData( Id, ParentId, Name )
Select Id, ParentId, Name
From Data
GO
Set Identity_Insert #TestData Off
GO
结果
id | parentid | name -- | -------- | ----------------- 1 | 0 | Food 2 | 1 | Taste 3 | 1 | Price 4 | 2 | Taste Requirement 5 | 0 | Copy Of Food 7 | 5 | Copy of Taste 8 | 5 | Copy of Price 9 | 7 | Copy of Taste Requirement
关于SQL - 克隆记录及其后代,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5943691/