June 2010
Intermediate to advanced
328 pages
7h 51m
English
Content preview from SQL AntipatternsBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Objective: Fetch a Sample Row
It’s surprising how frequently we need an SQL query that returns a random result. This seems to go against the principles of repeatability and deterministic programming. However, it’s ordinary to ask for a sample from a large data set. The following are some examples:
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Displaying rotating content, such as an advertisement or a news story to highlight
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Auditing a subset of records
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Assigning incoming calls to available operators
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Generating test data
It’s better to query the database for this sample, as an alternative to fetching the entire data set into your application just so you can pick a sample from the set.
The objective is to write an efficient SQL query that returns only a random sample of data. ...
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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.