--declare variables
declare @b bit
declare @i int

--select non initialized bit variable returns 0
select @b as "@b"

--assign bit variable into int variable
select @i=@b
--select int valiable returns NULL ! :(((
select @i as "@i"

--select NULL into bit variable. Strange but it's working...
select @b=null
--select the bit variable with NULL value returns 0
select @b as "@b=null"

--select 5 into bit. Still working...
select @b= 5 
--select of the bit variable with value "5" returns 1
select @b as "@b=5"

--assing 5 in bit to int
select @i=@b
--select returns 1
select @i as "@i=@b=5"