SQLite isn't a bad one to know at all. It's pretty close to PostgreSQL and PostgreSQL prides itself as caring about the SQL standard. I do think that, as gene

SQLite isn't a bad one to know at all. It's pretty close to PostgreSQL and PostgreSQL prides itself as caring about the SQL standard. I do think that, as general learning experience, working with PostgreSQL is a good starting place because of the good degree of SQL standard compliance. Get those basics down and the less standards compliant vendors become more accessible. After that it depends what kinda of companies you'd want to work for. Enterprises deal much in MSSQL and Oracle. Start-uppy kinds of companies you're looking at PostgreSQL or MySQL... Or something not RDBMS at all. There are many generalizations that can be made but these are a few hand-wavy examples I would make.