May 2025
Intermediate to advanced
270 pages
6h 55m
English
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Explaining EXPLAIN
Fortunately, most SQL implementations provideFortunately, most SQL implementations provide a tool that describes how a query will be executed by the database engine: the keyword EXPLAIN. Note that the response of EXPLAIN will differ between SQL implementations or even between different versions of the same database. The following examples are from MySQL 8.0.31. At the end of this section, we will look at some examples of the response returned by the other major implementation of SQL, Postgres.
ActiveRecord offers us an easy way to access the keyword while still using its API: just call .explain when executing a query, and you’ll get the analysis instead. Let’s take an extremely simple query, fetching an object by one of its ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.