How to get the value of autoincrement of last row

问题:

I have googled this problem one week and no thing useful I think am not using the correct word

I am using SQL Server 2008 with t-sql and my need is to optimise my function when I insert a new row.

I have a table with first column is the key of integer autoincrement type and other columns are just for information

When we do an insert, SQL Server increments the key automatically and I have to do a select max to get the value, so is there a way like a global variable like @@IDENTITY or a function to avoid the begin end transaction and select max

回答1:

Use SCOPE_IDENTITY:

-- do insert

SELECT SCOPE_IDENTITY();

Which will give you:

The last identity value inserted into an identity column in the same scope. A scope is a module: a stored procedure, trigger, function, or batch. Therefore, two statements are in the same scope if they are in the same stored procedure, function, or batch.

回答2:

Just ran the code:

INSERT INTO Persons (FirstName) VALUES ('Joe');
SELECT ID AS LastID FROM Persons WHERE ID = @@Identity;

and it also works!

回答3:

What about this for last auto increment value

SELECT IDENT_CURRENT('tableName')-IDENT_INCR('tableName');

回答4:

If you are using MySQL you get the auto increment ID of the last insert with:

SELECT LAST_INSERT_ID();

See here for full reference.

回答5:

In my case I had to use @@Identity, because I was inserting into a view. It seems that SCOPE_IDENTITY only works for ones you have explicitly created.

See here:

http://blog.sqlauthority.com/2007/03/25/sql-server-identity-vs-scope_identity-vs-ident_current-retrieve-last-inserted-identity-of-record/

@@IDENTITY will return the last identity value entered into a table in your current session. While @@IDENTITY is limited to the current session, it is not limited to the current scope. If you have a trigger on a table that causes an identity to be created in another table, you will get the identity that was created last, even if it was the trigger that created it.