How do I add the column before running this command in t-sql?

I have to write a script to update a database but im having problems doing it. The T-Sql i开发者_如何学Pythons

BEGIN TRY

    BEGIN TRANSACTION 

        ALTER TABLE company
        ADD RegistrationNumber nvarchar(50)

    COMMIT

END TRY
BEGIN CATCH
  IF(@@trancount > 0)
    ROLLBACK TRANSACTION 
END CATCH



update Company set RegistrationNumber = ''

But im getting the error

Invalid column name 'RegistrationNumber'.

However when I run the first bit then the second bit I dont get a problem....how do I get it all into one script?

---

When the parser analyses your query the RegistrationNumber field does not exist (yet) and so it reports the error; it would take a much more complex parser to recognise you are creating it earlier in the query.

Separate the two queries with GO and they will be parsed/executed individually, which should avoid the error.

BEGIN TRY
    BEGIN TRANSACTION 
        ALTER TABLE company
        ADD RegistrationNumber nvarchar(50)
    COMMIT
END TRY
BEGIN CATCH
  IF(@@trancount > 0)
    ROLLBACK TRANSACTION 
END CATCH

GO -- << Add this

UPDATE Company SET RegistrationNumber = ''

EDIT: If you want both steps to be performed in one go why not just use a default value for the new column?

BEGIN TRY
    BEGIN TRANSACTION 
        ALTER TABLE company
        ADD RegistrationNumber nvarchar(50) DEFAULT ''
    COMMIT
END TRY
BEGIN CATCH
  IF(@@trancount > 0)
    ROLLBACK TRANSACTION 
END CATCH