Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

I have a table that logs a record containing a userid, a fileid and a date, one record inserted every time that file is downloaded.<BR><BR>I want to get the top 10 downloads by count for a given date ...

Query federation is a way to make use of distributed data sources on the Web, including many SPARQL endpoints as well as relational databases. SWObjects makes use of mapping rules represented as ...