It is alright to say “No”
It can be hard to admit that you do not have experience with a particular technology or do not possess a particular skill. However, interviewers will appreciate it if you do not waste their time going off on a tangent because you are afraid to say No.
Be honest and to the point. I can respect an answer like, “I had a course in high school where we used COBOL but it has been 20 years.” I do not appreciate an answer that goes on about how they worked with someone at Initech that developed an application in COBOL and that they wrote a Web Service that delivered data from blah blah blah…
Know the basics
If you are selling yourself as a .NET developer, you better be able to answer questions about .NET basics. Review and have a general knowledge of topics like abstract classes, inheritance, System.Object, Reflection, and delegates.
For SQL, know about stored procedures, user defined functions, triggers, and views. Know about select query features: group by, having clause, union, join.
Prove that you understand the technologies that you are using by knowing the basics and terminology of the technology.
Know what’s on your resume
I interviewed a candidate who on his resume had a section on T-SQL stating that he had experience writing queries, stored procedures, user defined functions, views and triggers. When I started asking him questions about triggers, he started fumbling. Finally, I asked if he had ever written a trigger which he replied ‘no’. He just wasted 3 minutes of the interview and got himself some negative points.