An array whose elements specify a query to UNION, and the UNION type. The 'type' key may be '', 'ALL', or 'DISTINCT' to represent a 'UNION', 'UNION ALL', or 'UNION DISTINCT' statement, respectively.
All entries in this array will be applied from front to back, with the first query to union on the right of the original query, the second union to the right of the first, etc.
includes/ database/ select.inc, line 962
- Query builder for SELECT statements.
protected $union = array();