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  • 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
     
     
     
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  • 原文地址:https://www.cnblogs.com/hzcya1995/p/13316894.html
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