OCP-1Z0-051-V9.02-119题

119. Examine the data in the ORD_ITEMS table:

ORD_NO     ITEM_NO    QTY

1          111        10

1          222        20

1          333        30

2          333        30

2          444        40

3          111        40

Evaluate the following query: 

SQL>SELECT item_no, AVG(qty)

FROM ord_items

HAVING AVG(qty) > MIN(qty) * 2

GROUP BY item_no;

Which statement is true regarding the outcome of the above query?

A. It gives an error because the HAVING clause should be specified after the GROUP BY clause.

B. It gives an error because all the aggregate functions used in the HAVING clause must be specified in

the SELECT list.

C. It displays the item nos with their average quantity where the average quantity is more than double the

minimum quantity of that item in the table.

D. It displays the item nos with their average quantity where the average quantity is more than double the

overall minimum quantity of all the items in the table.

Answer: C

答案解析：

scott@TESTDB> select * from ord_items;

 

    ORD_NO    ITEM_NO        QTY

---------- ---------- ----------

         1        111         10

         1        222         20

         1        333         30

         2        333         30

         2        444         40

         3        111         40

 

6 rows selected.

scott@TESTDB> select item_no,avg(qty) from ord_items group by item_no;

 

   ITEM_NO   AVG(QTY)

---------- ----------

       222         20

       444         40

       333         30

       111         25

 

scott@TESTDB> select item_no,avg(qty) from ord_items having avg(qty)>min(qty)*2 group by item_no;

 

   ITEM_NO   AVG(QTY)

---------- ----------

       111         25