sqldf is an R package for runing SQL statements on R data frames, optimized for
convenience. The user simply specifies an SQL statement in R using data frame
names in place of table names and a database with appropriate table
layouts/schema is automatically created, the data frames are automatically
loaded into the database, the specified SQL statement is performed, the result
is read back into R and the database is deleted all automatically behind the
scenes making the database's existence transparent to the user who only
specifies the SQL statement.

WWW: https://code.google.com/p/sqldf