The CLSQL project was started by Kevin M. Rosenberg in 2001 to support SQL access on multiple Common Lisp implementations using the UFFI library. The initial code was based substantially on Pierre R. Mai's excellent MaiSQL package. In late 2003, the UncommonSQL library was orphaned by its author, onShore Development, Inc. In April 2004, Marcus Pearce ported the UncommonSQL library to CLSQL. The UncommonSQL library provides a CommonSQL-compatible API for CLSQL.

The main changes from MaiSQL and UncommonSQL are: