is there an easy to use formula for switching the datatype on a table column from int to bit?

Question

I'm looking at a sql server table, and one of the columns seems to have been setup to be of type INT NULL when it's really better off as a BIT NOT NULL.

Is there an easy formula or shortcut for switching the type?

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My current strategy is:

• add new temp column
• populate with data based on old column contents
• drop old column and constraints
• rename new column to old column name
• add constraints based on new column

this seems complicated but, really, should be automatable - so i'm wondering if anyone's automated it yet.

Answer 1

Update MyTable set MyColumn = 0 where MyColumn is null

Assuming you want null to be false

Alter table MyTable alter column MyColumn bit not null

Will do the job, given all non-zero values are to be treated as true.

Course you were going to backup before you did any of this weren't you. :)