So many times I have been asked for help with a query, where the question really comes down to the understanding of the difference between INNER and LEFT or RIGHT JOINs. I created this poster a few years ago and I keep it posted on the wall at the office. This way when I am trying to explain JOIN types, I just refer to the poster.
I have created the poster below to help describe JOIN types in My SQL. This had lead to lots of confusion over time, and this is the best way that I have seen to describe them.
If you are looking for the SQL Server version of this poster, click here.
Download JoinTypes.PDFDownload JoinTypes.PDF
If there is anything missing, please post a comment, there is room to add more to this poster.
Here is some of the feedback that I have received:
- This is one of the better and more complete posters out there. nice job! Having the code example is really useful too.