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.

Microsoft has just added support for query hints to Azure SQL Database, giving database administrators a powerful tool to manage the performance of ISV application code. Here's how it works.

This SQL feature allows you to query within a result set, creatively limit your result set, or correlate your results with an otherwise unrelated query in a single call to the database.