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  • Dustin Waybright thinks this is interesting:

The INTERSECT operator returns only distinct rows that are common to both sets. In other words, if a row appears at least once in the first set and at least once in the second set, it will appear once in the result of the INTERSECT operator.

From

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

Note

For instance, if you want to return a result of all cities where there are both customer location and dealer locations from a set of customer information and a set of dealer information.