How to combine 2 bit columns

I'm assuming col1 and col2 are bit values, the closest Sql Server has to booleans.

To return 1 or 0:

select case when col1=1 or col2=1 then 1 else 0 end
from yourtable

To return true or false:

select case when col1=1 or col2=1 then 'true' else 'false' end
from yourtable

You want to use Bitwsise operations

& - All conditions needs to match

| - Any condition needs to match

    Select 
    -- Both need to Match
    1 & 0,   -- false  
    1 & 1,   -- true
    -- Only one condition needs to match
    1 | 1,   -- true
    0 | 1,   -- true
    1 | 0,   -- true
    0 | 0   -- False

select col1 | col2 from myTable

http://msdn.microsoft.com/en-us/library/ms176122.aspx