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.
相关考题
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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);
