In which case would you use a FULL OUTER JOIN? ()

题目
单选题
In which case would you use a FULL OUTER JOIN? ()
A

Both tables have NULL values.

B

You want all unmatched data from one table.

C

You want all matched data from both tables.

D

You want all unmatched data from both tables.

E

One of the tables has more data than the other.

F

You want all matched and unmatched data from only one table.

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相似问题和答案

第1题:

Click the Exhibit button and examine the data in the EMPLOYEES and DEPARTMENTS tables.You want to retrieve all employees‘ last names, along with their managers‘ last names and their department names. Which query would you use?()

A.SELECT last_name, manager_id, department_name FROM employees e FULL OUTER JOIN departments d ON (e.department_id = d.department_id);

B.SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.manager_id = m.employee_id) LEFT OUTER JOIN departments d ON (e.department_id = d.department_id);

C.SELECT e.last_name, m.last_name, department_name FROM employees e RIGHT OUTER JOIN employees m on ( e.manager_id = m.employee_id) LEFT OUTER JOIN departments d ON (e.department_id = d.department_id);

D.SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGHT OUTER JOIN departments d ON (e.department_id = d.department_id);

E.SELECT e.last_name, m.last_name, department_name FROM employees e RIGHT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGHT OUTER JOIN departments d ON (e.department_id = d.department_id);

F.SELECT last_name, manager_id, department_name FROM employees e JOIN departments d ON (e.department_id = d.department_id) ;


参考答案:B

第2题:

Redo log files are multiplexed in your database. The disk in which you have one of the redo log members is highly fragmented. In the process of defragmentation you lose the redo log member, which is not a member of the current group. How would you recover from the loss of the redo log member?()

  • A、SMON would automatically restore the lost file.
  • B、You would need to restore the whole database from the last backup.
  • C、You would need to restore the file from the last full database backup.
  • D、You would need to use flashback technology to restore the lost redo log member.
  • E、You would need to use Recovery Manager (RMAN) to restore the lost redo log member.
  • F、You would need to restore the missing log file by copying one of the remaining files from the same group.

正确答案:F

第3题:

In which case would you use a FULL OUTER JOIN? ()

A. Both tables have NULL values.

B. You want all unmatched data from one table.

C. You want all matched data from both tables.

D. You want all unmatched data from both tables.

E. One of the tables has more data than the other.

F. You want all matched and unmatched data from only one table.


参考答案:D

第4题:

下列连接中能自动删除重复的列是()。

  • A、INNER JOIN
  • B、LEFT OUTER JOIN
  • C、RIGHT OUTER JOIN
  • D、FULL OUTER JOIN

正确答案:A

第5题:

In which two cases would you use an outer join? ()

  • A、The tables being joined have NOT NULL columns.
  • B、The tables being joined have only matched data.
  • C、The columns being joined have NULL values.
  • D、The tables being joined have only unmatched data.
  • E、The tables being joined have both matched and unmatched data.
  • F、Only when the tables have a primary key-foreign key relationship.

正确答案:C,E

第6题:

In which three cases would you use the USING clause?()

  • A、You want to create a nonequijoin.
  • B、The tables to be joined have multiple NULL columns.
  • C、The tables to be joined have columns of the same name and different data types.
  • D、The tables to be joined have columns with the same name and compatible data types.
  • E、You want to use a NATURAL join, but you want to restrict the number of columns in the join condition.

正确答案:C,D,E

第7题:

You want the size of the tablespace to increase when it is full. Which option would you use?()

  • A、use automatic extent allocation
  • B、disable threshold for the tablespace
  • C、use freelists to manage the free space
  • D、use automatic segment space management
  • E、create the tablespace as a bigfile tablespace
  • F、use the RESIZE clause while creating the tablespace
  • G、enable AUTOEXTEND for at least one of the data files in the tablespace

正确答案:G

第8题:

ExhibitExamine the data in the EMPLOYEES and DEPARTMENTS tables.You want to retrieve all employees‘ last names, along with their manager‘s last names and their department names. Which query would you use?()

A. SELECT last_name, manager_id, department_name FROM employees e FULL OUTER JOIN department d ON (e.department_id = d.department_id);

B. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.managaer_id = m.employee_id) LEFT OUTER JOIN department d ON (e.department_id = d.department_id);

C. SELECT e.last_name, m.last_name, department_name FROM employees e RIGT OUTER JOIN employees m on ( e.manager_id = m.employee_id) FULL OUTER JOIN department d ON (e.department_id = d.department_id);

D. SELECT e.last_name, m.last_name, department_name FROM employees e LEFT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGT OUTER JOIN department d ON (e.department_id = d.department_id);

E. SELECT e.last_name, m.last_name, department_name FROM employees e RIGHT OUTER JOIN employees m on ( e.manager_id = m.employee_id) RIGHT OUTER JOIN departments d ON (e.department_id = d.department_id)

F. SELECT last_name, manager_id, department_name FROM employees e JOIN department d ON (e.department_id = d.department_id);


参考答案:B

第9题:

Which three are true regarding the use of outer joins? ()

  • A、You cannot use IN operator in a condition that involves an outerjoin.
  • B、You use (+) on both sides of the WHERE condition to perform an outerjoin.
  • C、You use (*) on both sides of the WHERE condition to perform an outerjoin.
  • D、You use an outerjoin to see only the rows that do not meet the join condition.
  • E、In the WHERE condition, you use (+) following the name of the column in the table without matching rows, to perform an outerjoin.
  • F、You cannot link a condition that is involved in an outerjoin to another condition by using the OR operator.

正确答案:D,E,F

第10题:

以下哪两组联接关键字可以创建这样一个联接,该联接包括SELECT语句中指定的第一个表中的不匹配行?()

  • A、LEFT OUTER JOIN和FULL OUTER JOIN
  • B、RIGHTOUTERJOIN和LEFT OUTER JOIN
  • C、USING和HAVING
  • D、OUTER JOIN和USING

正确答案:A

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