■■ Predicates with fullselects.
■■ Special registers like CURRENT TIMESTAMP.
■■ GROUPING SETS, CUBE, and ROLLUP are supported. The GROUP BY items and associated GROUPING column functions in the select list must form a unique key of the result set. Thus, the following restrictions must be satisfied:
■■ No grouping sets may be repeated. For example,
ROLLUP(X,Y),X is not allowed because it is equivalent to GROUPING SETS((X,Y),(X),(X)).
■■ If REPLICATED is specified, the table must have a unique key.
■■ When a GROUP BY clause is not specified, the following unique-ness related restriction applies: The materialized view’s non-duplicate requirement is achieved by deriving a unique key for the MQT from one of the unique key constraints defined in each
|DB2 Materialized Query Tables||249|
■■ MQTs cannot be used as exception tables to collect information when constraints are being validated during bulk constraints check-ing (during LOAD or executing the SET INTEGRITY statement).