Types of Joins - Know the Code

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SQL provides you with four different commands to join database tables together: INNER JOIN, LEFT JOIN, RIGHT JOIN, and JOIN. How do these work? What makes them different? And when do you use one or the other? Let’s relate it to WordPress posts and metadata as well as posts to terms.

This chart provides a visual of the what is fetched for each join:
SQL Joins Diagram

Additional Resources:

Break. Go rest your noodle for a couple of minutes.

Episodes

Total Lab Runtime: 02:46:48

1 Lab Introductionfree 14:27
2 Slow Approach Overviewpro 12:11
3 Test Slow Approach - Part 1pro 17:27
4 Test Slow Approach - Part 2pro 21:07
5 Relational Typespro 23:20
6 Types of Joinspro 09:30
7 Joining Metadatapro 12:37
8 Joining Posts to Termspro 20:32
9 Grouping Datasetspro 08:32
10 WordPress SQL Handler $wpdbpro 11:01
11 Deeper Dive into $wpdb->get_resultspro 05:54
12 Run Fast Approach & Compare Resultspro 10:10

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