Where are Cartesian Joins used in real life?

join, sql

Solution

just random example. you have a table of cities: Id, Lat, Lon, Name. You want to show user table of distances from one city to another. You will write something like

SELECT c1.Name, c2.Name, SQRT( (c1.Lat - c2.Lat) * (c1.Lat - c2.Lat) + (c1.Lon - c2.Lon)*(c1.Lon - c2.Lon))
FROM   City c1, c2

Problem

Where are Cartesian Joins used in real life? Can some one please give examples of such a Join in any SQL database.

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