[nopinsight]

Are you talking about CS undergrad degree holders or CS PhDs?

Some CS undergrads might have chosen CS without commensurating aptitudes and interest, and graduated without much skills. Same goes for other majors at the undergrad level. They are a mixed bag with great and inadequate graduates receiving the same degree.

Also, did you look at their undergrad performance (GPA, research papers, senior project)? They can be more indicative than the degree itself.

PhDs are a whole different ball game. At least they are usually good at problem solving. They might not know SQL off-hand (since they never needed to learn it) but give them a day or a couple of hours to learn, they should be able the master the basics pretty well.