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：
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