以下是OCP教材中對該函數的描述
RTRIM(<c1>,<c2> ) takes two arguments, where c1 and c2 are character
strings. This function returns c1 without any trailing characters that appear
in c2. If no c2 characters are trailing characters in c1, then c1 is returned
unchanged. c2 defaults to a single space.
大家對Rtrim捨去字符串右邊的空字符串是毫無疑議的
有疑問的應該是右邊是字符串如何處理的。
如:
SELECT RTRIM('Mississippi','ip') test1,RTRIM('Rpadded ') test2 ,RTRIM('Mississippi','sip') test3 FROM dual;
結果爲:
test1 test3 test3
Mississ Rpadded M
test1的實現
首先從字符串'Mississippi'右邊查找'ip'中的任意字符,此例爲'i','p',直到'Mississippi'右邊不爲'i'和'p'字符爲止,所以結果應該是Mississ
test2的實現
去掉字符串的空格
test3的實現
實現方法同test1首先從字符串'Mississippi'右邊查找'sip'中的任意字符,此例爲's','i','p',直到'Mississippi'右邊不爲's'、'i'和'p'字符爲止,所以結果應該是M
可以通過下例進一步瞭解Rtrim函數
SELECT RTRIM('Mississippi','Misp') test1,RTRIM('Mississippi','i') test2 FROM dual;
test1 test2
Mississipp
本文來自CSDN博客,轉載請標明出處:http://blog.csdn.net/rfb0204421/archive/2008/12/02/3430916.aspx