出自:Oracle认证
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) DEFAULT 'SA_REP' SAL NUMBER COMM_PCT NUMBER MGR_ID NUMBER DEPARTMENT_ID NUMBER You need to update the records of employees 103 and 115. The UPDATE statement you specify should update the rows with the values specified below: JOB_ID: Default value specified for this column definition. SAL: Maximum salary earned for the job ID SA_REP. COMM_PCT: Default value specified for this commission percentage column, if any. If no default value is specified for the column, the value should be NULL. DEPARTMENT_ID: Supplied by the user during run time through substitution variable. Which UPDATE statement meets the requirements?（）
A:UPDATE employees SET job_id = DEFAULT AND Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') AND comm_pct = DEFAULT AND department_id = &did WHERE employee _id IN (103,115);
B:UPDATE employees SET job_id = DEFAULT AND Sal = MAX(sal) AND comm_pct = DEFAULT OR NULL AND department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
C:UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP'), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115);
D:UPDATE employees SET job_id = DEFAULT, Sal = MAX(sal), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
E:UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') comm_pct = DEFAULT OR NULL, department_id = &did WHERE employee_id IN (103,115);
Click the Exhibit button and examine the data from the ORDERS and CUSTOMERS tables. Which SQL statement retrieves the order ID, customer ID, and order total for the orders that are placed on the same day that Martin placed his orders?（）
A:SELECT ord_id, cust_id, ord_total FROM orders, customers WHERE cust_name='Martin' AND ord_date IN ('18-JUL-2000','21-JUL-2000');
B:SELECT ord_id, cust_id, ord_total FROM orders WHERE ord_date IN (SELECT ord_date FROM orders WHERE cust_id = (SELECT cust_id FROM customers WHERE cust_name = 'Martin'));
C:SELECT ord_id, cust_id, ord_total FROM orders WHERE ord_date IN (SELECT ord_date FROM orders, customers WHERE cust_name = 'Martin');
D:SELECT ord_id, cust_id, ord_total FROM orders WHERE cust_id IN (SELECT cust_id FROM customers WHERE cust_name = 'Martin');
Which statement is correct about the database?（）
Which statement is true about the effect of the above command?（）
Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: 
What is true about your ALTER statement?（）