Someone will probably tell me that this is an elementary-level topic, but I got some good questions regarding joins from my most recent ZCE class students, so I thought I'd put down the examples that I used to explain this to them. Being able to join with confidence is a key skill, because it means that you can refactor and normalise your data, without worrying about how hard something will be to retrieve.

The database structure I'm using here looks like this (the same example that I used when I wrote the Databases chapter for PHP Master):

If you want to grab the actual data I'm using for my examples, then here's the zipped mysqldump file: …

Someone will probably tell me that this is an elementary-level topic, but I got some good questions regarding joins from my most recent ZCE class students, so I thought I’d put down the examples that I used to explain this to them. Being able to join with confidence is a key skill, because it means that you can refactor and normalise your data, without worrying about how hard something will be to retrieve.

The database structure I’m using here looks like this (the same example that I used when I wrote the Databases chapter for PHP Master):

If you want to grab the actual data I’m using for my examples, then here’s the zipped mysqldump file: …