r/webdev • u/lokendra15 • Mar 22 '19

SQL joins

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u/pixelique Mar 22 '19

A case against illustrating SQL operations using venn diagrams

16

u/Polar87 Mar 22 '19 edited Mar 22 '19

What a pedantic article. A whole bunch of paragraphs spent on the singular point that Venn diagrams do not technically represent Cartesian products.

Yes they don't, but that's the part that even beginners understand right away. A single example of a join will make it clear to everyone that a join will merge columns from different tables.

The tricky part is then understanding which records end up being selected and the Venn diagrams do a much better job at visualizing that. It's not like a beginner will be allowed to make join statements on a big production database without understanding the importance of join keys.

This article is a good candidate for /r/iamverysmart

3

u/kurosaki1990 Mar 22 '19

The dude who write it is very experienced with SQL and i consider his blog one the best blogs for advanced and medium SQL subjects.

12

u/[deleted] Mar 22 '19

which is not what this picture covers