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  • Dustin Waybright thinks this is interesting:

Note the importance of aliasing the tables in the join. For one, it’s convenient to refer to a table by using a shorter name. But in a self-join like ours, table aliasing is mandatory.

From

Cover of Training Kit (Exam 70-461): Querying Microsoft® SQL Server® 2012

Note

self-join is joining a table to itself.