OCP-1Z0-051-V9.02-79题

79. View the Exhibit and examine the structure of the CUSTOMERS table.

In the CUSTOMERS table, the CUST_LAST_NAME column contains the values 'Anderson' and 'Ausson'.

You issue the following query:

SQL> SELECT LOWER(REPLACE(TRIM('son' FROM cust_last_name),'An','O'))      

FROM CUSTOMERS     

WHERE LOWER(cust_last_name) LIKE 'a%n';

What would be the outcome? 

A. 'Oder' and 'Aus'

B. a n error because the  TRIM function specified is not valid

C. a n error because the  LOWER function specified is not valid

D. a n error because the  REPLACE function specified is not valid

Answer: B

 答案解析：

参考：http://blog.csdn.net/rlhua/article/details/12848395

TRIM：截去字符串首字符或尾字符（或者两者都截去）（如果trim_character或trim_source 是一个字符文字，则必须将其放在单引号内）

实验验证：

sh@TESTDB> select trim('son' from cust_last_name) from customers ;

select trim('son' from cust_last_name) from customers

       *

ERROR at line 1:

ORA-30001: trim set should have only one character

 

 

sh@TESTDB> select trim('s' from cust_last_name) from customers where rownum<3;

 

TRIM('S'FROMCUST_LAST_NAME)

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

Ruddy

Ruddy

 

 

sh@TESTDB> select trim('sa' from 'saabd') from dual;

select trim('sa' from 'saabd') from dual

       *

ERROR at line 1:

ORA-30001: trim set should have only one character

 

 

sh@TESTDB> select trim('s' from 'saabd') from dual;

 

TRIM

----

aabd