单项选择题
Examine the data from the ORDERS and CUSTOMERS table. Which SQL statement retrieves the order ID, customer ID, and order total for the orders that are placed on the same day that Martin places his orders?（）
A. B. C. D.
Evaluate the SQL statement: 1 SELECT a.emp_name, a.sal,...
Evaluate the SQL statement: 1 SELECT a.emp_name, a.sal, a.dept_id, b.maxsal 2 FROM employees a, 3 (SELECT dept_id, MAX(sal) maxsal 4. FROM employees 5 GROUP BY dept_id) b 6 WHERE a.dept_id = b.dept_id 7 AND a. asl < b. maxsal; What is the result of the statement?（）
A. The statement produces an error at line 1. B. The statement produces an error at line 3. C. The statement produces an error at line 6. D. The statement returns the employee name, salary, department ID, and maximum salary earned in the department of the employee for all departments that pay less salary then the maximum salary paid in the company. E. The statement returns the employee name, salary, department ID, and maximum salary earned in the department of the employee for all employees who earn less than the maximum salary in their department.
You need to modify the STUDENTS table to add a primary ...
单项选择题You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty.Which statement accomplishes this task?（）
A. ALTER TABLE students ADD PRIMARY KEY student_id; B. ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student _ id); C. ALTER TABLE students ADD CONSTRAINT stud _ id _pk PRIMARY KEY (student _ id); D. ALTER TABLE students MODIFY CONSTRAINT stud _ id _pk PRIMARY KEY (student _ id);
The EMPLOYEE tables has these columns: You want to dis...
The EMPLOYEE tables has these columns: 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;
