From the website: "... xlSQL is a JDBC Driver for Excel ( CSV, XML and other ) document data sources. Documents can be read and written with SQL as if they were tables in a database. In the case of Excel, xlSQL maps a directory with Excel files to a database, workbooks to schemas, and sheets to tables. These tables can be queried with the full SELECT syntax of either the HSQLDB or MySQL (more to follow) SQL dialect. Native xlSQL is a rich subset of SQL for creating, altering and populating documents ( spreadsheets ). ..." ( One could argue xlSQL is MySQL with Excel files. )

http://xlsql.dev.java.net