select rtrim('morning','ning') from dual;和select rtrim('morn

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select rtrim('morning','ning') from dual;和select rtrim('morning','ing') from dual;为什麼结果一样
oracle 中 rtrim 该怎麼使用.为什麼上面两个句子出现的结果是一样的 ,

RTRIM（c1,c2）的含义是从c1的右边删去c2中出现的任意一个字符,直到c1的右边不再出现c2中的任意一个字符.
c1是'morning',c2是'ning' .c2中的任意一个字符在c1的右边出现都要删除,直到没有c2中的任意一个字符.从g开始检测,g在c2中有,n在c2中也有,i也有,n也有,直到检测到r,c2中没有r.所以结果为mor.同理select rtrim('morning','ing') from dual; 的结果也为mor.
再给你个例子细细体会吧.
SELECT RTRIM('Mississippi','ip') test1,RTRIM('Rpadded ') test2 ,RTRIM('Mississippi','sip') test3 FROM dual;
结果是：
T1 T2 T3
------- ----------- --
Mississ Rpadded M

insert into REC_OVER(ORG_ID) select '1' from dual where not select from 表和select from [表]有什么不同? ms sql :select * from (select *from b) as xxx where 和 select SELECT oracle trunc函数没法精确到小时 select trunc(sysdate,'hh') from dual select*from ‘ * ’ 的意义? select * from book limit , insert into a select * from b 和select * into a from b 这两个语句是 SELECT sum(1) FROM table;和SELECT count(1) FROM table; 数据库中select into from 和 insert into select的区别 SELECT MAX(account) AS account FROM shop 和 SELECT MAX(accoun select t.*和select *有什么不同