Imply bit with constant 1 or 0 in SQL Server

Question

Is it possible to express 1 or 0 as a bit when used as a field value in a select statement?

e.g.

In this case statement (which is part of a select statement) ICourseBased is of type int.

case 
when FC.CourseId is not null then 1
else 0
end
as IsCoursedBased

To get it to be a bit type I have to cast both values.

case 
when FC.CourseId is not null then cast(1 as bit)
else cast(0 as bit)
end
as IsCoursedBased

Is there a short hand way of expressing the values as bit type without having to cast every time?

(I'm using MS SQL Server 2005)

Answer 1

No, but you could cast the whole expression rather than the sub-components of that expression. Actually, that probably makes it less readable in this case.

Answer 2

Unfortunately, no. You will have to cast each value individually.

Answer 3

cast 
(
case 
when FC.CourseId is not null then 1 else 0 end --fixed during edit. oops
 as bit)

The CAST spec is "CAST (expression AS type)". The CASE is an expression in this context.

If you have multiple such expressions, I'd declare bit vars @true and @false and use them. Or use UDFs if you really wanted...

DECLARE @True bit, @False bit;
SELECT @True = 1, @False = 0;  --can be combined with declare in SQL 2008

SELECT
    case when FC.CourseId is not null then @True ELSE @False END AS ...

Answer 4

You might add the second snippet as a field definition for ICourseBased in a view.

DECLARE VIEW MyView
AS
  SELECT
  case 
  when FC.CourseId is not null then cast(1 as bit)
  else cast(0 as bit)
  end
  as IsCoursedBased
  ...

SELECT ICourseBased FROM MyView