Union « Set Operations « SQL Server / T-SQL Tutorial

6.3.1.Using Unions to Display Data from Multiple Queries
6.3.2.Listing the output from two identical tables.
6.3.3.UNION same type of columns from different tables
6.3.4.A union that combines information from the Billings table
6.3.5.A union that combines payment data from the same joined tables
6.3.6.OR operator can be used instead of the UNION operator, as the two equivalent examples.