Besides simple queries, MINUS or EXCEPT can be used within the following operations:
- Derived tables You cannot use the HASH BY or LOCAL ORDER BY clauses in derived tables with set operators.
- INSERT … SELECT statements
- View definitions
MINUS and EXCEPT cannot be used within the following operations:
- SELECT AND CONSUME statements.
- WITH RECURSIVE clause
- CREATE RECURSIVE VIEW statements
Each query connected by MINUS or EXCEPT is executed to produce a result consisting of a set of rows. The exception must include the same number of columns from each table in each SELECT statement (more formally, they must be of the same degree), and the data types of these columns should be compatible. All the result sets are then combined into a single result set, which has the data types of the columns specified in the first SELECT statement in the exception.