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 ...

SQL SELECT statement. The SELECT statement tells the query optimizer what data to return, what tables to look in, ... So far, I’ve described the SELECT syntax for single tables.

Anyone who has seen a ten- or twenty-page SQL SELECT statement can attest to this SQL mosaic-ability. Sadly, this simple and elegant aspect leads to confusion among many who should know better. While ...