CAML查询以查找嵌套在文档库树中的特定SPFolder

It seems like searching with CAML and SPQuery doesn't work properly against custom metadata, when searching for SPFolders instead of files, or when searching for custom content types. I've been using U2U to test a variety of queries, and just not getting anywhere. The doc's aren't very complete on the topic, and google isn't helping either.It seems like searching with CAML and SPQuery d