How do I get the Identity field that results from an insert?

问题

I'm going to insert data into a table like so:

Insert Into MyTable (Field1, Field2)
           Values   ('test', 5)

When that insert occurs, the new row is going to have an identify value in the ID column. If have a variable called @ID in my T-SQL code, how do I populate @ID with the result of the T-SQL Insert?

Declare @ID int

Insert into MyTable (Field1, Field2)
             Values ('test', 5)

--//How do I populate @ID with the value of ID of the record that was just inserted?

回答1:

There are two ways - the first is to use SCOPE_IDENTITY:

DECLARE @ID INT

INSERT INTO MyTable (Field1, Field2)
VALUES ('test', 5)

SELECT @ID = SCOPE_IDENTITY() 

Don't use @@IDENTITY -- the value it contains is for the last updated IDENTITY column without regard for scope. Meaning, it's not reliable that it holds the value for your INSERT, but SCOPE_IDENTITY does.

The other alternative is to use the OUTPUT clause (SQL Server 2005+).

回答2:

SELECT @ID = SCOPE_IDENTITY();

回答3:

You should use scope_identity in your case.

There are different ways to get last inserted identity and they differ in how they work just for your information listing them -

1. @@IDENTITY

2. SCOPE_IDENTITY()

3. IDENT_CURRENT

4. OUTPUT CLAUSE (came to know about it from @OMG Ponies answer)

Consider the differences and comparisons between them before deciding which one to use.

来源：https://stackoverflow.com/questions/4157142/how-do-i-get-the-identity-field-that-results-from-an-insert