Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement.

Apache Hive: This is the original SQL-on-Hadoop solution, which tries to emulate the behavior, syntax, and interface (s) of MySQL, including a command-line client. It also includes a Java API and ...

There are significant differences in the implementation logic, character set support, and usage details of VARCHAR among various databases, with SQL Server and PostgreSQL being particularly ...