单选题Which of the following SQL statements will return the year and average salary for all employees hired within a given year that have a salary greater than $30,000?（）A SELECT * FROM t1 UNION SELECT * FROM t2B SELECT * FROM t1 UNION DISTINCT SELECT * FROM

A.SELECT * FROM employees where salary > (SELECT MIN(salary) FROM employees GROUP BY department_id);

B.SELECT * FROM employees WHERE salary = (SELECT AVG(salary) FROM employees GROUP BY department_id);

C.SELECT distinct department_id FROM employees WHERE salary > ANY (SELECT AVG(salary) FROM employees GROUP BY department_id);

D.SELECT department_id FROM employees WHERE salary > ALL (SELECT AVG(salary) FROM employees GROUP BY department_id);

E.SELECT last_name FROM employees WHERE salary > ANY (SELECT MAX(salary) FROM employees GROUP BY department_id);

F.SELECT department_id FROM employees WHERE salary > ALL (SELECT AVG(salary) FROM employees GROUP BY AVG(SALARY));

A.SELECT * FROM t1 UNION SELECT * FROM t2

B.SELECT * FROM t1 UNION DISTINCT SELECT * FROM t2

C.SELECT * FROM t1 INTERSECT SELECT * FROM t2

D.SELECT * FROM t1 WHERE (c1,c2)= (SELECT c1,c2 FROM t2)

The EMPLOYEE tables has these columns:LAST_NAME VARCHAR2(35)SALARY NUMBER(8,2)COMMISSION_PCT NUMBER(5,2)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;

A.SELECT UNIQUE dept FROM staff

B.SELECT DISTINCT dept FROM staff

C.SELECT (dept) UNIQUE FROM staff

D.SELECT (dept) DISTINCT FROM staff

A.SELECT * FROM t1 UNION SELECT * FROM t2

B.SELECT * FROM t1 UNION DISTINCT SELECT * FROM t2

C.SELECT * FROM t1 INTERSECT SELECT * FROM t2

D.SELECT * FROM t1 WHERE (c1,c2)= (SELECT c1,c2 FROM t2)

A.SELECT * FROM T1 MINUS SELECT * FROM T2

B.SELECT * FROM T1 EXCEPT SELECT * FROM T2

C.SELECT * FROM T2 UNION EXCEPT SELECT * FROM T1

D.SELECT * FROM T1 NOT EXISTS SELECT * FROM T2

A. SELECT * FROM employees where salary > (SELECT MIN(salary) FROM employees GROUP BY department _ id);

B. SELECT * FROM employees WHERE salary = (SELECT AVG(salary) FROM employees GROUP BY department _ id);

C. SELECT distinct department_id FROM employees Where salary > ANY (SELECT AVG(salary) FROM employees GROUP BY department _ id);

D. SELECT department_id FROM employees WHERE SALARY > ALL (SELECT AVG(salary) FROM employees GROUP BY department _ id);

E. SELECT last_name FROM employees Where salary > ANY (SELECT MAX(salary) FROM employees GROUP BY department _ id);

F. SELECT department_id FROM employees WHERE salary > ALL (SELECT AVG(salary) FROM employees GROUP BY ANG (SALARY));