1Z0-007章節(jié)練習(xí)(2020.05.19)

Evaluate these two SQL statements:
SELECT last_name, salary , hire_date
FROM EMPLOYEES
ORDER BY salary DESC;
SELECT last_name, salary, hire_date
FROM EMPLOYEES
ORDER BY 2 DESC;
What is true about them? （）

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 DEPARTMENT_ID = NULL;
What is true about this SQL statement ?（）

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 ( employe_id NUMBER, name VARCGAR2(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 sey name = 'James' Where employee_id=180;
Rollback;
At the end of this transaction, what is true?（）

Click the Exhibit button and examine the data in the EMPLOYEES table.
Examine the subquery:
SELECT last_name
FROM employees
WHERE salary IN (SELECT MAX(salary)
FROM employees
GROUP BY department_id);
Which statement is true?（）

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?（）