SQL Server obtains the ID of the inserted record (automatic number)

Recently, I encountered a problem in the development project, that is, after inserting a record, I need to immediately obtain the ID in the database, which is auto-incrementing. How can I do this? There are several methods available in SQL Server 2005.

The simplest way to obtain this ID is to select @ indentity after the query.

-- SQL statement to create databases and tables
Create Database dbdemo
Go
Use dbdemo
Go
Create Table tbldemo
(
Id int Primary Key Identity (1, 1 ),
Name varchar (20)
)
Go

-- Execute the following SQL statement to check the values of the auto-incrementing column corresponding to the inserted record.
Insert into tbldemo values ('test') Select @ identity

SQL Server 2000 has three similar functions: scope_identity, ident_current, and @ identity. They both return values inserted into the identity column.
1) ident_current returns the final id value generated for any session and a specific table in any scope. It is not restricted by the scope and session, but by the specified table.
2) @ identity returns the final id value generated for any table in all scopes of the current session.
3) scope_identity returns the last generated id value for the current session and any table in the current scope.
Scope_identity and @ identity return the last id value generated in any table in the current session. However, scope_identity only returns the value inserted into the current scope; @ identity is not limited to a specific scope.
For example, there are two tables T1 and T2, and an insert trigger is defined on T1. When a row is inserted to T1, the trigger is triggered and a row is inserted to T2. This example illustrates two scopes: insert on T1 and insert on T2 as the trigger result.
Assume that both T1 and T2 have the identity column. @ identity and scope_identity return different values at the end of the insert Statement on T1. @ Identity returns the value of the last identity column inserted to any scope in the current session. This value is the value inserted in T2.