In earlier versions of Adaptive Server, union operators in select statements that define views were not supported. Adaptive Server version 12.5 removes this restriction.
You might use this feature, for example, to split a large table into subtables. The data can be partitioned between the subtables based on ranges of data values in one of the columns. You can then define a view that uses union all to combine selects of all the subtables into a single result set. You can then issue select statements on the view containing the union.
You can create views that reference Oracle, DB2, and Informix tables, for example, as well as local tables
