A. They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.
B. They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.
C. They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.
D. The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true.

A. They can accept only one argument.
B. They can be nested up to only two levels.
C. They can return multiple values of more than one data type.
D. They can be used in SELECT， WHERE， and ORDER BY clauses.  
E. They can modify the data type of the argument that is referenced.
F. They can accept a column name， expression， variable name， or a user-supplied constant as arguments.

A. When a table is dropped， the corresponding indexes are automatically dropped.
B. For each DML operation performed， the corresponding indexes are automatically updated.
C. Indexes should be created on columns that are frequently referenced as part of an expression.
D. A non-deferrable PRIMARY KEY or UNIQUE KEY constraint in a table automatically creates a uniqueindex.

A. PUBLIC should be replaced with specific usernames.
B. ALL should be replaced with a list of specific privileges.
C. WITH GRANT OPTION should be added to the statement.
D. Separate GRANT statements are required for ORDERS and ORDERJTEMS tables.

A. displaying the total order value for sales representatives 161 and 163
B. displaying the order total for sales representative 161 in the year 1999
C. displaying the number of orders that have order mode online and order date in 1999
D. displaying the number of orders whose order total is more than the average order total for all online orders

A. The statement would not execute because table aliases are not allowed in the JOIN clause.
B. The statement would not execute because the table alias prefix is not used in the USING clause.
C. The statement would not execute because all the columns in the SELECT clause are not prefixed with table aliases.
D. The statement would not execute because the column part of the USING clause cannot have a qualifier in the SELECT list.

A. os
B. local
C. -8：00
D. dbtimezone Li
E. Australia

A. They are evaluated by all the three WHEN clauses regardless of the results of the evaluation of any other WHEN clause.
B. They are evaluated by the first WHEN clause. If the condition is true， then the row would be evaluated by the subsequent WHEN clauses.
C. They are evaluated by the first WHEN clause. If the condition is false， then the row would be evaluated by the subsequent WHEN clauses.
D. The INSERT statement would give an error because the ELSE clause is not present for support in case none of the WHEN clauses are true.

A. It returns versions of rows only within a transaction.
B. It can be used in subqueries contained only in a SELECT statement.
C. It will return an error if the undo retention time is less than the lower bound time or SCN specified.
D. It retrieves all versions including the deleted as well as subsequently reinserted versions of the rows.

A. It would be automatically enabled and deferred.
B. It would be automatically enabled and immediate.
C. It would remain disabled and has to be enabled manually using the ALTER TABLE command.
D. It would remain disabled and can be enabled only by dropping the foreign key constraint and re-creating it.