When you execute a query using the LEFT JOIN syntax, SQL does two things: It returns all of the records from both tables that contain matching values, as defined by the ON clause.

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 ...

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 ...

SQL Server 2016 lets you treat JSON objects like rows in a table, allowing you to use data from AJAX queries in joins, updates and any other SQL statement you can think of. SQL Server 2016 provides ...

When I looked at CockroachDB 1.1.3 at the beginning of 2018, its SQL JOIN implementation was limited to hash joins and a heuristic planner; its query performance often scaled linearly but was ...

SQL Server 2022 takes that ability a few steps further. Last year, I wrote a column on the introduction of query store hints into Azure SQL Database.