A good programmer should be an expert in some fields and at the same time knows a lot of other things. If a Java programmer tells his boss that writing SQL statements is not his duty, I don't think his boss will be happy.
Indeed, everybody has his good points and shortcomings. Job interview is not only a test of job candidtates' knowledge, but also a benchmarking of his personalities. It is very important for us to know how to express our different opinions and how to display our qualifications.