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Simon Willison’s Weblog

A Visual Explanation of SQL Joins. It turns out Venn diagrams are an excellent way of illustrating joins.

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2 comments

  1. It's no coincidence - relational theory is an offshoot of set theory.

    Simon Brunning - 12th October 2007 11:14 - #

  2. I'd be interested to hear an explanation of how the analogy breaks down (as hinted at in some of the comments).

    Jason Davies - 12th October 2007 15:01 - #

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