SQL Behind the Curtain: How Are Queries Executed?
Explore the journey of your SQL query guided by execution plans
Imagine your SQL query is like a treasure map, and the database is a huge area to explore. The execution plan is like a detailed route created by an expert navigator (the SQL engine) to help you find the treasure (your query results) as quickly as possible. Understanding this route lets you spot shortcuts, avoid wrong turns, and reach your goal faster.
By understanding SQL execution plans and the basics of Big O notation, you can optimise your queries to be faster and more effective.
In this post, we will explore how SQL Queries are executed behind the scenes.
What is Big O Notation?
Big O notation describes the performance of an algorithm in terms of how it scales with the size of the input. It provides a high-level understanding of the time or space complexity, helping us evaluate the efficiency of different operations.
While you don’t need to be a computer scientist to write SQL, knowing the relative costs of operations helps when optimising queries.