Select 

case 

    when a=1 and b=0 THEN 'True'

    when a=1 and b=1 then 'Trueish'

    when a=0 and b=0 then 'False'

    when a=0 and b=1 then 'Falseish'

    else null

end AS Result

FROM tableName

Select

case

    when a=1 then

        case 

            when b=0 then 'True'

            when b=1 then 'Trueish'

        end

    When a=0 then

        case

            when b=0 then 'False'

            when b=1 then 'Falseish'

        end

    else null

end AS Result

FROM tablename

Select 

case 

    when a=1 and b=0 THEN 'True'

    when a=1 and b=1 then 'Trueish'

    when a=0 and b=0 then 'False'

    when a=0 and b=1 then 'Falseish'

    else null

end AS Result

FROM tableName

Select 

case 

    when a=1 and b=0 THEN 'True'

    when a=1 and b=1 then 'Trueish'

    when a=0 and b=0 then 'False'

    when a=0 and b=1 then 'Falseish'

    else null

end AS Result

FROM tableName