OCP-1Z0-051-V9.02-153题

153. View the Exhibits and examine the structures of the PRODUCTS and SALES tables.

Which two SQL statements would give the same output? (Choose two.)

A. SELECT prod_id FROM products

INTERSECT

SELECT prod_id FROM sales;

B. SELECT prod_id FROM products

MINUS

SELECT prod_id FROM sales;

C. SELECT DISTINCT  p.prod_id

FROM products p JOIN sales s

ON p.prod_id=s.prod_id;

D. SELECT DISTINCT p.prod_id

FROM products p JOIN sales s

ON p.prod_id <> s.prod_id;

Answer: AC

答案解析：

A：所有的产品和已卖出的产品相交，即返回已经卖出去的产品的id。

sh@TEST0924> SELECT prod_id FROM products

  2  INTERSECT

  3  SELECT prod_id FROM sales;

 

   PROD_ID

----------

        13

        14

        15

        16

...

       148

 

72 rows selected.默认升序排列。

 

B:所有的产品和已卖出去的产品相减，即返回没有卖出去的产品。

sh@TEST0924> SELECT prod_id FROM products

  2  MINUS

  3  SELECT prod_id FROM sales;

 

no rows selected

 

 

C:返回已卖出去的产品的id

sh@TEST0924> SELECT DISTINCT  p.prod_id

  2   FROM products p JOIN sales s

  3  ON p.prod_id=s.prod_id;

 

   PROD_ID

----------

        22

        25

 

...

       139

 

72 rows selected.

 

D答案：会把所有的都显示出来

sh@TEST0924> SELECT DISTINCT p.prod_id

  2  FROM products p JOIN sales s

  3  ON p.prod_id <> s.prod_id;

 

 

   PROD_ID

----------

        13

        14

...

       148

 

72 rows selected.

 

 

INTERSECT Example The following statement combines the results with the INTERSECT operator, which returns only those unique rows returned by both queries

返回共同有的唯一的行

MINUS Example The following statement combines results with the MINUS operator, which returns only unique rows returned by the first query but not by the second

返回第一个有，第二个表无的行

官方参考：http://docs.oracle.com/cd/E11882_01/server.112/e41084/queries004.htm#i2054381