多项选择题

Which three statements about subqueries are true?（）

A. A single row subquery can retrieve only one column and one row.
B. A single row subquery can retrieve only one row but many columns.
C. A multiple row subquery can retrieve multiple rows and multiple columns.
D. A multiple row subquery can be compared by using the ">" operator.
E. A single row subquery can use the IN operator.
F. A multiple row subquery can use the "=" operator.

点击查看答案

上一题目录下一题

相关考题

多项选择题

When should you create a role? （）

A. To simplify the process of creating new users using the CREATE USER xxx IDENTIFIED by yyy statement.
B. To grant a group of related privileges to a user.
C. When the number of people using the database is very high.
D. To simplify the process of granting and revoking privileges.
E. To simplify profile maintenance for a user who is constantly traveling.

单项选择题

Which clause would you use in a SELECT statement to limit the display to those employees whose salary is greater then 5000? （）

A. ORDER BY SALARY > 5000
B. GROUP BY SALARY > 5000
C. HAVING SALARY > 5000
D. WHERE SALARY > 5000

单项选择题

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
DEPARTMENT_ID NUMBER
SALARY NUMBER
What is the correct syntax for an inline view? （）

A. SELECT a.last_name, a.salary, a.department_id, b.maxsal FROM employees a, (SELECT department_id, max(salary)maxsal FROM employees GROUP BY department_id) b WHERE a.department_id = b.department_id AND a.salary < b.maxsal;
B. SELECT a.last name, a.salary, a.department_id FROM employees a WHERE a.department_id IN (SELECT department_id FROM employees b GROUP BY department_id having salary = (SELECT max(salary) from employees))
C. SELECT a.last_name, a.salary, a.department_id FROM employees a WHERE a.salary = (SELECT max(salary) FROM employees b WHERE a.department _ id = b.department _ id);
D. SELECT a.last_name, a.salary, a.department_id FROM employees a WHERE (a.department_id, a.salary) IN (SELECT department_id, a.salary) IN (SELECT department_id max(salary) FROM employees b GROUP BY department_id ORDER BY department _ id);