Union Views

A view that contains a UNION or UNION ALL operator in its SELECT statement is known as a union view. Certain restrictions apply to union views:

• If a CREATE VIEW statement defines a union view, you cannot specify the WITH CHECK OPTION keywords in the CREATE VIEW statement.
• All restrictions that apply to UNION or UNION ALL operations in stand-alone SELECT statements also apply to UNION and UNION ALL operations in the SELECT statement of a union view.

For a list of these restrictions, see Restrictions on a Combined SELECT. For an example of a CREATE VIEW statement that defines a union view, see Naming View Columns.