OCP-1Z0-051-V9.02-169题

169. View the Exhibit and examine the description for the PRODUCTS and SALES table.

PROD_ID is a primary key in the PRODUCTS table and foreign key in the SALES table. You want to

remove all the rows from the PRODUCTS table for which no sale was done for the last three years.

Which is the valid DELETE statement? 

A. DELETE

FROM products

WHERE prod_id = (SELECT prod_id                 

FROM sales                 

WHERE time_id - 3*365 = SYSDATE ); 

B. DELETE

FROM products

WHERE prod_id = (SELECT prod_id                 

FROM sales                 

WHERE SYSDATE >= time_id - 3*365 );

C. DELETE

FROM products

WHERE prod_id IN (SELECT prod_id                  

FROM sales                  

WHERE SYSDATE - 3*365 >= time_id);  

D. DELETE

FROM products

WHERE prod_id IN (SELECT prod_id                  

FROM sales                  

WHERE time_id >= SYSDATE - 3*365 );

Answer: C

 答案解析：

题意要求：从PRODUCTS表移除所有过去三年没有销售过的产品行

SYSDATE - 3*365 <= time_id三年前之前的时间，三年前多，

SYSDATE - 3*365 >= time_id三年前之后的时间，三年前往后面数， 即应该用这个

即选C