What is the value of is_pod?

>Hi everybody,
>
>I am not sure why I am getting the error 'can not implicitly convert string booking type to Boolean') when I try to apply C# iif as in this command
>
>

>sqlCommand.CommandText = "SELECT * FROM dbo.b_sched WHERE " + columnName + 
>                  @" = @columnValue and start_time IS NOT NULL 
>                       AND layer < 7 and is_pod" + ("POD"== bookingType)?">0":"=0";

>
>bookingType defined as String.
>
>Do you see what is wrong in this expression and why C# doesn't like it?