单项选择题
View the Exhibit and examine the structure of the ORDERS table.
Which task would require subqueries？ （）
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
相关考题
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多项选择题
Whichstatementsarecorrectregardingindexes？（）
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. -
单项选择题
Evaluate the following SQL statements that are issued in the given order： What would be the status of the foreign key EMP_MGR_FK？（）
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. -
单项选择题
WhichstatementistrueregardingFlashbackVersionQuery？（）
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.
