CONSIDER THIS COMPOUND QUERY

15. Consider this compound query:

select empno, hired from empunion allselect emp_id,hired,fired from ex_emp;

The columns EMP.EMPNO and EX_EMP.EMP_ID are integer; the column

EMP.HIRED is timestamp; the columns EX_EMP.HIRED and EX_EMP.FIRED

are date. Why will the statement fail? (Choose the best answer.)

A. Because the columns EMPNO and EMP_ID have different names

B. Because the columns EMP.HIRED and EX_EMP.HIRED are different

data types

C. Because there are two columns in the first query and three columns in the

second query

D. For all of the reasons above

E. The query will succeed