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 ...

Multiple Detail Records - 4 in this case. (linked to the header record) Multiple Inventory Records - again, 4 - (each detail record points to one specific inventory record, but the inventory may be ...

Follow this step-by-step guide to install PostgreSQL, load data, connect to a database, and execute SQL queries including table joins PostgreSQL is an open-source, object-relational (also called ...

A common SQL habit is to use SELECT * on a query, because it’s tedious to list all the columns you need. Plus, sometimes those columns may change over time, so why not just do things the easy way? But ...

SQL is about as easy as it gets in the world of programming, and yet its learning curve is still steep enough to prevent many people from interacting with relational databases. Salesforce’s AI ...

PolyBase, a data virtualization feature for SQL Server, allows users to seamlessly query data from various external sources directly using T-SQL (Transact-SQL) without the need for separate client ...