The EMP table contains these columns: EMPLOYEE_ID NUMBER(4) EMPNAME VARCHAR2 (25) SALARY NUMBER(9,2) HIRE_DATE DATE You query the database with this SQL statement: SELECT empname,hire_date HIREDATE, salary FROM EMP ORDER BY hire_date; How will the results

第1题：

第2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.

第3题：

第4题：

The EMP table has these columns: ENAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATE Management wants a list of names of employees who have been with the company for more than five years. Which SQL statement displays the required results? （）

• A、SELECT ENAME FROM EMP WHERE SYSDATE-HIRE_DATE >5;
• B、SELECT ENAME FROM EMP WHERE HIRE_DATE-SYSDATE >5;
• C、SELECT ENAME FROM EMP WHERE (SYSDATE_HIRE_DATE)/365 >5;
• D、SELECT ENAME FROM EMP WHERE (SYSDATE_HIRE_DATE)*/365 >5;

第5题：

The EMPLOYEES table contains these columns: LAST_NAME VARCHAR2 (25) SALARY NUMBER (6,2) COMMISSION_PCT NUMBER (6) You need to write a query that will produce these results: 1. Display the salary multiplied by the commission_pct. 2. Exclude employees with a zero commission_pct. 3. Display a zero for employees with a null commission value. Evaluate the SQL statement: SELECT LAST_NAME, SALARY*COMMISSION_PCT FROM EMPLOYEES WHERE COMMISSION_PCT IS NOT NULL; What does the statement provide? （）

• A、All of the desired results
• B、Two of the desired results
• C、One of the desired results
• D、An error statement

第6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 INSERT statement is valid?（）

• A、INSERT INTO employees (employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01/01/01);
• B、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01 january 01');
• C、INSERT INTO employees(employee_id, first_name, last_name, Hire_date) VALUES (1000, 'John', 'smith', To_ date ('01/01/01));
• D、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01-Jan-01');

第7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;

第8题：

第9题：

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employee_id NUMBER, name VARCHAR2(30)); INSERT INTO new_emp SELECT employee_id , last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id =180; UPDATE new_emp set name = 'James'; Rollback to s2; UPDATE new_emp set name = 'James' WHERE employee_id =180; Rollback; At the end of this transaction, what is true?（）

• A、You have no rows in the table.
• B、You have an employee with the name of James.
• C、You cannot roll back to the same savepoint more than once.
• D、Your last update fails to update any rows because employee ID 180 was already deleted.

第10题：

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.