The EMP table contains these columns: LAST NAME VARCHAR2(25) SALARY NUMBER(6,2) DEPARTMENT_ID NUMBER(6) You need to display the employees who have not been assigned to any department. You write the SELECT statement: SELECT LAST_NAME, SALARY, DEPARTMENT_ID FROM EMP WHERE DEPARMENT_ID = NULL; What is true about this SQL statement? （）

A、The SQL statement displays the desired results.

B、The column in the WHERE clause should be changed to display the desired results.

C、The operator in the WHERE clause should be changed to display the desired results.

D、The WHERE clause should be changed to use an outer join to display the desired results.

相关问题推荐

• 在PowerPoint中，幻灯片放映时要有对象进入放映界面的动画效果，应选择（）动画效果设置。

  A、 进入

  B、 强调

  C、 退出

  D、 动作路径

  查看答案

• Which statement is true about a whole consistent database backup on a database running in ARCHIVELOG mode（）

  A、The backup will consist of used data blocks only.

  B、The database must be shut down to accomplish the backup.

  C、The backup can be accomplished without shutting down the database.

  D、The backup will contain all database files that have never been backed up.

  查看答案

• 制图国家标准规定，图纸幅面尺寸应优先选用（）几种基本幅面尺寸。

  A、3

  B、4

  C、5

  D、6

  查看答案

• 对于二维数组a［1..6，1..8］，设每个元素占2个存储单元，且以列为主序存储，则元素a［4，4］相对于数组空间起始地址的偏移量是（）个存储单元。

  A、28

  B、42

  C、48

  D、54

  查看答案

• Which of the following is the MOST secure method to authenticate users?（）

  A、User ID, a strong password, and a fingerprint scanner

  B、User ID, a strong password, and a token based device

  C、User ID and two levels of strong password requirements

  D、User ID, a strong password, and a smart card

  查看答案