Union « Set « Oracle PL/SQL Tutorial

3.5.1.Using the UNION Operator
3.5.2.UNION with order by clause
3.5.3.Use UNION to connect column data and summary data
3.5.4.Produce a summary of the grouped aggregate by using set functions
3.5.5.Union with table join
3.5.6.Union date column
3.5.7.Using union in subquery
3.5.8.Combining Data with UNION for single column