This Oracle tutorial explains how to use the Oracle/PLSQL TRIM function.
The Oracle/PLSQL TRIM function removes all specified characters either from the beginning or the ending of a string.
TRIM removes a set of characters from both sides of a string.
The general format for this function is:
TRIM ([where] [trim_character] FROM subject string)
The optional where is one of the keywords "leading", "trailing", or "both". If the optional trim_character is not present, then blanks will be trimmed. The word FROM is necessary only if where or trim_character is present. Trim character may be any character.
Both the leading and trailing spaces are deleted.
SQL> SELECT TRIM (' abc ') FROM dual;
TRI
---
abc
SQL>
We can add the "both" keyword:
SQL> SELECT TRIM (both ' ' from ' abc ') FROM dual;
TRI
---
abc
SQL>
In the following examples, characters rather than spaces are trimmed:
SQL> SELECT TRIM('F' from 'Friday is a Day') FROM dual;
-- w w w.jav a 2 s. com
TRIM('F'FROM'F
--------------
riday is a Day
SQL> SELECT TRIM(trailing 's' from 'Cars') FROM dual;
TRI
---
Car
SQL>
Using "leading" keyword.
SQL> SELECT TRIM(leading 'F' from 'Friday Father Further') FROM dual;
-- from ww w . j ava 2 s . c om
TRIM(LEADING'F'FROM'
--------------------
riday Father Further
SQL>
Nesting TRIM functions:
SQL> SELECT TRIM(trim(both 'a' from 'a abc')) FROM dual;
TRI
---
abc
SQL>