choose three
Examine this SQL statement:
SELECT custid, cus last_name "Last Name"
FROM customers
WHERE country_id = 10
UNION
SELECT cust_id CUST_NO, cust_last_name
FROM customers
WHERE country_id = 30
Identify three ORDER BY clauses, any one of which can complete the query successfully.
A) ORDERBY 2, 1
B) ORDER BY "CUST_NO"
C) ORDER BY 2,cust_id
D) ORDER BY CUST_NO
E) ORDER BY "Last Name"
Answer：ACE
(Analysis: This problem is resolved with the following resolution, the answer is to find out the summary in accordance with the law of resolution.)
071-140 Title:
SELECT department_id "DEPT_ID", department_name, 'b' FROM departments
WHERE department_id=90 UNION
SELECT department_id, department_name DEPT_NAME, 'a' FROM departments
WHERE department_id=10
Which two ORDER BY clauses can be used to sort output?
A. ORDER BY DEPT_NAME;
B. ORDER BY DEPT_ID;
C. ORDER BY 'b';
D. ORDER BY 3;
Correct Answer: BD
(Analysis: found experimentally alias must be enclosed in double quotes summed up before they can be used to sort; and found took the name alias (alias outlined by double quotation marks) columns can not be used to sort; no summarized in double quotes column aliases may be used to sort; order by 3, can be sorted according to the order of the display column.
Note union ordered to write in order by the time the final statement; sort found only in the first select statement in the column. )
SQL> select empno "CUST_NO",ename "LAST NAME",'a' FROM emp
2 UNION
3 SELECT EMPNO ,ENAME,'b' FROM emp
4 ORDER BY empno;
ORDER BY empno
*
Line 4 errors:
ORA-00904: "EMPNO": identifier is invalid