SQL Group By

SQL Group By

Author: Trevor Page: Java Guru | Programmer | Teacher June 16, 2014 Duration: 47:00

After having talked about all the SQL Aggregate functions, there's one more topic that goes hand in hand with what we've already learned… The group by keyword.

This particular keyword allows us to take a bunch of data and mash it all together into matching groups and then perform aggregate functions on those groups (like sum and avg).

You might ask yourself why you'd want to "mash together" a bunch of data. The answer to this is best explained with an example, but let me try to put it in regular words before we jump into our example. Grouping data together allows us to look at aggregate data in relation to unique piece of data (or rows), a typical use case would be to group all the matching data together so you can get a count of the number of occurrences of specific data. An example related to grouping and counting could be a presidential election, you'll have all the votes in a database and you'll want to group that data together to get the total votes for each unique candidate...

For more info, check out the show notes via http://howtoprogramwithjava.com/session48

 


The How to Program with Java Podcast is a practical guide for anyone wanting to build software, from curious beginners to those looking to solidify their professional skills. Host Trevor Page, a seasoned Java guru and teacher, breaks down complex programming concepts into clear, manageable lessons you can apply immediately. You'll hear detailed walkthroughs on building applications, understanding core principles like object-oriented design, and navigating the tools of the trade. The discussions move beyond dry theory, focusing on the real-world logic and problem-solving that defines a career in software development. Whether you're aiming for a new job, tackling a personal project, or helping a child explore technology, this podcast provides a structured, conversational path forward. Each episode is crafted to demystify the process, translating technical jargon into plain English so you can focus on creating functional code. The tone is direct and encouraging, rooted in Trevor's experience as both a programmer and an educator. It’s a resource for building a tangible skill set, episode by episode, where consistent listening translates directly to growing competency. You’ll find the content naturally bridges the categories of technology education and career development, making it a useful companion for your learning journey.
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