HTSQL a high-level query language and Web service gateway for relational databases. It comes with source code and is royalty free for any use with open source database systems such as MySQL, PostgreSQL, SQLite, etc. Licenses for using HTSQL in conjunction with proprietary databases such as Microsoft SQL and Oracle can be purchased.
Recent releases


Release Notes: Licensing and packaging were updated. HTSQL is now free software under the AGPLv3 for SQLite, PostgreSQL, and MySQL.


Release Notes: This release adds a Web-based query editor with completion and syntax highlighting, as well as a Python API for embedded applications.


Release Notes: This release adds the ability to override database catalog meta-data, adds table/column/link name auto-completion to the editor, and adds Django integration.


Release Notes: This release focuses on supporting analytical queries with projections and calculated attributes.


Release Notes: This release added a mechanism for querying HTSQL's system catalog, and a query editor for the Web with syntax highlighting.