SQL DBA :- It is kind of Admin role, you need to maintain the SQL server performance, security, backup restore, installation, patching etc.,, very low you have to do some programming .. so it is kind of system admin of SQL SERVER.

SQL Dev :- Need programming work. In dev you need to write a sql skripts to create, stored proc, trigger, views etc, so you must have a knowledge of SQL skript language, this job required more logical concepts rather then admin.

Hope this will help you..