New posts in Union

Using SQL JOIN and UNION together

Incorrect usage of UNION and ORDER BY?

ActiveRecord Query Union

SQL: how to use UNION and order by a specific select?

How can I get the intersection, union, and subset of arrays in Ruby?

Intersection and union of ArrayLists in Java

MySQL: FULL OUTER JOIN - How do I merge one column?

How to write UNION in Doctrine 2.0

SELECT INTO USING UNION QUERY

SQL Server: ORDER BY in subquery with UNION