A Visual Explanation of SQL Joins

It’s really great article!!!

Muy bueno este articulo !! Los grficos ayudan mucho a enterder.
Gracias !
Desde Argentina, Buenos Aires.

it was great explanation , i do like the way u explained using venndiag , superb understaning on subj after long time , it was refreshing , pls do keep posting …thnx sumanth

2 THUMBS UP for this work

Thanks a lot for your effort. Now i am confident about joins i mean basic concepts… this article is the best.

Thank you very much jeff. I was always confuused about these joins. Today I have got clear idea about inner ande outer joins.

Great work. Now i can visualize my big query’s into circles. Good.

Best of rest,

Your explanation on SQL Join helped me a lot to complete my project easily. I was struggling to find out an exact query to match my requirement.

Thanks a lot

So what is the volumetric shape of a circle multiplied by a circle?

Good and simple explanation of joins my fears of joins are erased
Thank you

very informative.

Its a really interesting article… Joins was really confusing all the time and u have presented it in a very simple manner… i gothrough some books like silbershwats and all but they have given it in very complex manner… and u are simply great… Please prsent such wonderfull article again sir… Thankyou very much.

very useful article

Very helpful…

Thanks Jeff. Very useful and simple explanation.

Khup Chaan

Very elegant and easy explanation. congratulations, Very useful!

I’d say the post achieves the authors purpose. I thought to myself WTF is the difference between those bloody joins again? and find this, 15 seconds later I remember all of the CS lore I needed. I don’t want to put words in the authors mouth (page?) but I doubt he was thinking of the diagrams in terms of their mathematical correctness to set theory when he put this together, simply trying to demonstrate the difference between the joins, which it achieved very well.

Once modification that might make you all happy, though. Just imagine an undrawn Z axis along which the seeming-circle of the diagram can expand to hold all of the duplicate values on each side making a sort of three dimensional blob. Then imagine this as the 2 dimensional representation, and it all works. Yay!

Very useful. Thanks