When I visit a new file, ^xf, that has an extension of .sql or .dsql I would like the coding system to be set to
utf-8-with-signature-dos. The default is currently
"GNU Emacs 24.3.1 (i386-mingw-nt6.1.7601)\n of 2013-03-17 on MARVIN"
Both the .sql and .dsql extension start up sql-mode, but I doubt a hook off of sql mode is the appropriate place to change the coding system for new files.