插入连接标识列与其他列
Inserting concatenate Identity column with other column
I have a identity column and i have other column while inserting a new row in
table i need to insert into third column with concatenate of two columns result
参考如下table
------------------------------------------------
A | B | c
----------------------------------------------
1 | 33 | 133(1 [identity result] + 33)
2 | 112 | 2112
请帮我解决这个问题。
无需插入C列，使用Select语句即可轻松获取C列。
像这样。
select A,B,cast(Cast(A as varchar(max))+cast(B as varchar(max)) as
varchar(max)) as C from Your_Table_Name
如果你真的需要插入C列，那么你必须运行同时插入和更新查询，以在table的C列中插入值。
喜欢：
insert into Table_Name(B) values('33');Select IDENT_CURRENT();
--you'll get the inserted Identity.
--now run the Update query for Identity you get from the insert query.
示例。
create table #tab1
(
Id bigint identity(1,1) primary key,
a int,
b varchar(50)
)
insert into #tab1(a) values(88);
declare @id1 as bigint set @id1=(select SCOPE_IDENTITY());
update #tab1 set b=cast(id as varchar(max))+cast(a as varchar(max)) where Id=@id1
这个问题已经有了答案，但我认为这不是最好的答案。
这是一个关于如何使用 computed column 实现它的示例。
CREATE TABLE dbo.calculatedTEST (
A INT IDENTITY(1,1) NOT NULL,
B INT NOT NULL,
c AS CONVERT(INT,CONVERT(VARCHAR(max),A)+CONVERT(VARCHAR(max),B))
)
insert into dbo.calculatedTEST
(B)
values
(1),
(1),
(2),
(2)
select * from dbo.calculatedTEST
A computed column is computed from an expression that can use other
columns in the same table. The expression can be a noncomputed column
name, constant, function, and any combination of these connected by
one or more operators. The expression cannot be a subquery.
Unless otherwise specified, computed columns are virtual columns that
are not physically stored in the table. Their values are recalculated
every time they are referenced in a query. The Database Engine uses
the PERSISTED keyword in the CREATE TABLE and ALTER TABLE statements
to physically store computed columns in the table. Their values are
updated when any columns that are part of their calculation change. By
marking a computed column as PERSISTED, you can create an index on a
computed column that is deterministic but not precise. Additionally,
if a computed column references a CLR function, the Database Engine
cannot verify whether the function is truly deterministic. In this
case, the computed column must be PERSISTED so that indexes can be
created on it. For more information, see Creating Indexes on Computed
Columns.
I have a identity column and i have other column while inserting a new row in
table i need to insert into third column with concatenate of two columns result
参考如下table
------------------------------------------------
A | B | c
----------------------------------------------
1 | 33 | 133(1 [identity result] + 33)
2 | 112 | 2112
请帮我解决这个问题。
无需插入C列，使用Select语句即可轻松获取C列。
像这样。
select A,B,cast(Cast(A as varchar(max))+cast(B as varchar(max)) as
varchar(max)) as C from Your_Table_Name
如果你真的需要插入C列，那么你必须运行同时插入和更新查询，以在table的C列中插入值。
喜欢：
insert into Table_Name(B) values('33');Select IDENT_CURRENT();
--you'll get the inserted Identity.
--now run the Update query for Identity you get from the insert query.
示例。
create table #tab1
(
Id bigint identity(1,1) primary key,
a int,
b varchar(50)
)
insert into #tab1(a) values(88);
declare @id1 as bigint set @id1=(select SCOPE_IDENTITY());
update #tab1 set b=cast(id as varchar(max))+cast(a as varchar(max)) where Id=@id1
这个问题已经有了答案，但我认为这不是最好的答案。
这是一个关于如何使用 computed column 实现它的示例。
CREATE TABLE dbo.calculatedTEST (
A INT IDENTITY(1,1) NOT NULL,
B INT NOT NULL,
c AS CONVERT(INT,CONVERT(VARCHAR(max),A)+CONVERT(VARCHAR(max),B))
)
insert into dbo.calculatedTEST
(B)
values
(1),
(1),
(2),
(2)
select * from dbo.calculatedTEST
A computed column is computed from an expression that can use other columns in the same table. The expression can be a noncomputed column name, constant, function, and any combination of these connected by one or more operators. The expression cannot be a subquery.
Unless otherwise specified, computed columns are virtual columns that are not physically stored in the table. Their values are recalculated every time they are referenced in a query. The Database Engine uses the PERSISTED keyword in the CREATE TABLE and ALTER TABLE statements to physically store computed columns in the table. Their values are updated when any columns that are part of their calculation change. By marking a computed column as PERSISTED, you can create an index on a computed column that is deterministic but not precise. Additionally, if a computed column references a CLR function, the Database Engine cannot verify whether the function is truly deterministic. In this case, the computed column must be PERSISTED so that indexes can be created on it. For more information, see Creating Indexes on Computed Columns.