单选题The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY ( SALARY

题目
单选题
The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: ALTER TABLE EMPLOYEES MODIFY ( SALARY DEFAULT 5000); What is true about your ALTER statement?（）
A

Column definitions cannot be altered to add DEFAULT values.

B

A change to the DEFAULT value affects only subsequent insertions to the table.

C

Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.

D

All the rows that have a NULL value for the SALARY column will be updated with the value 5000.

相似考题

1.The EMPLOYEE tables has these columns:LAST_NAME VARCHAR2(35)SALARY NUMBER(8,2)COMMISSION_PCT NUMBER(5,2)You want to display the name and annual salary multiplied by the commission_pct for all employees. For records that have a NULL commission_pct, a zero must be displayed against the calculated column.Which SQL statement displays the desired results? （）A. SELECT last_name, (salary * 12) * commission_pct FROM EMPLOYEES;B. SELECT last_name, (salary * 12) * IFNULL(commission_pct, 0) FROM EMPLOYEES;C. SELECT last_name, (salary * 12) * NVL2(commission_pct, 0) FROM EMPLOYEES;D. SELECT last_name, (salary * 12) * NVL(commission_pct, 0) FROM EMPLOYEES;

2.单选题Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) Which statement produces the number of different departments that have employees with last name Smith? （）A SELECT COUNT (*) FROM employees WHERE last _name='smith';B SELECT COUNT (dept_id) FROM employees WHERE last _name='smith';C SELECT DISTINCT (COUNT (dept_id) FROM employees WHERE last _name='smith';D SELECT COUNT (DISTINCT dept_id) FROM employees WHERE last _name='smith';E SELECT UNIQE (dept_id) FROM employees WHERE last _name='smith';

3.单选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid?（）A UPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;B UPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;C UPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;D UPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;

4.单选题You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees; （）A You get an error because of a primary key violation.B The data and structure of the EMPLOYEES table are deleted.C The data in the EMPLOYEES table is deleted but not the structure.D You get an error because the statement is not syntactically correct.

参考答案和解析
正确答案： B
解析： 暂无解析
更多“The EMPLOYEES table has these columns: LAST NAME VARCHAR2(35”相关问题

  • 第1题：

    单选题
    The EMPLOYEES table has these columns:LAST_NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATEManagement wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement:ALTER TABLE EMPLOYEES MODIFY (SALARY DEFAULT 5000);Which is true about your ALTER statement?（）
    A

    Column definitions cannot be altered to add DEFAULT values.

    B

    A change to the DEFAULT value affects only subsequent insertions to the table.

    C

    Column definitions cannot be altered to add DEFAULT values for columns with a NUMBER data type.

    D

    All the rows that have a NULL value for the SALARY column will be updated with the value 5000.


    正确答案： B
    解析： 暂无解析

  • 第2题：

    单选题
    The EMPLOYEES table contains these columns: EMPLOYEE_ID NUMBER(4) LAST_NAME VARCHAR2 (25) JOB_ID VARCHAR2(10) You want to search for strings that contain 'SA_' in the JOB_ID column. Which SQL statement do you use?（）
    A

    SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA/_%' ESCAPE '/';

    B

    SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA_';

    C

    SELECT employee_id, last_name, job_id FROM employees WHERE job_id LIKE '%SA_' ESCAPE /;

    D

    SELECT employee_id, last_name, job_id FROM employees WHERE job_id = '%SA_';


    正确答案： B
    解析： 暂无解析

  • 第3题：

    单选题
    Management has asked you to calculate the value 12*salary* commission_pct for all the employees in the EMP table. The EMP table contains these columns: LAST NAME VARCNAR2(35) NOT NULL SALARY NUMBER(9,2) NOT NULL COMMISION_PCT NUMBER(4,2) Which statement ensures that a value is displayed in the calculated columns for all employees?（）
    A

    SELECT last_name, 12*salary* commission_pct FROM emp;

    B

    SELECT last_name, 12*salary* (commission_pct,0) FROM emp;

    C

    SELECT last_name, 12*salary*(nvl(commission_pct,0)) FROM emp;

    D

    SELECT last_name, 12*salary*(decode(commission_pct,0)) FROM emp;


    正确答案： B
    解析： 暂无解析

  • 第4题：

    单选题
    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which UPDATE statement is valid?（）
    A

    UPDATE employees SET first_name = 'John' SET last_name ='Smith' WHERE employee_id = 180;

    B

    UPDATE employees SET first_name = 'John', SET last_name ='Smith' WHERE employee_id = 180;

    C

    UPDATE employees SET first_name = 'John' AND last_name ='Smith' WHERE employee_id = 180;

    D

    UPDATE employees SET first_name = 'John', last_name ='Smith' WHERE employee_id = 180;


    正确答案： B
    解析： 暂无解析

  • 第5题：

    多选题
    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）
    A

    INSERT INTO employees VALUES (NULL, 'JOHN','Smith');

    B

    INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');

    C

    INSERT INTO employees VALUES ('1000','JOHN','NULL');

    D

    INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');

    E

    INSERT INTO employees (employee_id) VALUES (1000);

    F

    INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',);


    正确答案： A,F
    解析： 暂无解析

  • 第6题：

    单选题
    The EMPLOYEE tables has these columns: LAST_NAME VARCHAR2(35) SALARY NUMBER(8,2) COMMISSION_PCT NUMBER(5,2) You want to display the name and annual salary multiplied by the commission_pct for all employees. For records that have a NULL commission_pct, a zero must be displayed against the calculated column. Which SQL statement displays the desired results?（）
    A

    SELECT last_name, (salary * 12) * commission_pct FROM EMPLOYEES;

    B

    SELECT last_name, (salary * 12) * IFNULL(commission_pct, 0) FROM EMPLOYEES;

    C

    SELECT last_name, (salary * 12) * NVL2(commission_pct, 0) FROM EMPLOYEES;

    D

    SELECT last_name, (salary * 12) * NVL(commission_pct, 0) FROM EMPLOYEES;


    正确答案： C
    解析： 暂无解析

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