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A Practical Guide to Linux® Commands, Editors, and Shell Programming, Third Edition by Mark G. Sobell

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Joins

A join operation combines rows from/across two or more related tables in a database according to some relationship between these tables. (Refer to the join utility [page 843] for information on joining text files from the command line.) Take the maxdb database, for example: The people table has columns that hold information about employee name, hire date, store the employee works at, and whether the employee is hourly (as opposed to salaried); the stores table has columns that hold information about the store name, number, and city it is located in. With this setup, you cannot determine which city an employee works in by querying either the people or stores table alone; you must join the tables to get this information.

You join tables using ...

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