PostgreSQL: The world's most advanced open source database.
Oracle | Software. Hardware. Complete. Jaro-Winkler’s Algorithm Part One, Oracle utl_match Built-in Function at Waldar's SQLing and Datawarehousing Place. A Visual Explanation of SQL Joins. I love the concept, though, so let's see if we can make it work. Assume we have the following two tables. Table A is on the left, and Table B is on the right. We'll populate them with four records each. id name id name -- ---- -- ---- 1 Pirate 1 Rutabaga 2 Monkey 2 Pirate 3 Ninja 3 Darth Vader 4 Spaghetti 4 Ninja Let's join these tables by the name field in a few different ways and see if we can get a conceptual match to those nifty Venn diagrams.
There's also a cartesian product or cross join, which as far as I can tell, can't be expressed as a Venn diagram: SELECT * FROM TableA CROSS JOIN TableB This joins "everything to everything", resulting in 4 x 4 = 16 rows, far more than we had in the original sets. Tech on the Net. Various stuff.