Programmatically set identity seed in a table variable

Question

I need to create a table variable with an identity seed that starts with the max value of a field in another table?

I\'ve tried this:

DECLARE @Identi         


        

Answer 1

I believe you can do this, but it'll have to be done in dynamic SQL - declare the tableVar in the dynamic SQL and use it there too!

It would surely be easier and result in faster code if you started it at 1 and had a secondary ID field that is calculated as MAX(HHRecId) + ID.

Answer 2

I ended up doing the following:

DECLARE @NewId INT

SELECT @NewId = MAX(ID) FROM MyIDSTable

DECLARE @MyTempData TABLE (
    Id int not null primary key
    ,Field1 int not null
    ,Field2 nvarchar(25) not null
    ,Field3 datetime
)

INSERT INTO @MyTempData
SELECT  ROW_NUMBER() OVER ( Order by [C].[Cancel_id] ASC) + @NewId -1 [RowNum]
        ,Field1
        ,Field2
        ,Field3

INSERT INTO MyTable SELECT * FROM @MyTempData

UPDATE MYIDSTable SET ID = (SELECT MAX(ID) FROM @MyTempData) + 1 WHERE Name = 'Something'

Thank you

Answer 3

You can check the current value of an IDENTITY column by using:

DBCC CHECKIDENT (#HH)

and you can also change that later on using:

DBCC CHECKIDENT (#HH, RESEED, 42)

and that also works with a variable for the new value:

DBCC CHECKIDENT (#HH, RESEED, @IdentitySeed)

It works for local and global temporary tables (i.e. CREATE TABLE #HH (...) or CREATE TABLE ##HH (....) - but it doesn't seem to work with table variables :-(

Sorry, it seems you can't do this with table variables.....