ORACLE TRIM 详解【转】

In Oracle/PLSQL, the trim function removes all specified characters either from the beginning or the ending of a string.

The syntax for the trim function is:

trim( [ leading | trailing | both  [ trim_character ]  ]   string1 )

leading - remove trim_string from the front of string1.

trailing - remove trim_string from the end of string1 .

both - remove trim_string from the front and end of string1 .

If none of these are chosen (ie: leading, trailing, both), the trim function will remove trim_string from both the front and end of string1

 

trim_character is the character that will be removed from string1 . If this parameter is omitted, the trim function will remove all leading and trailing spaces from string1 .

string1 is the string to trim.

 

For example:

trim('   tech   ')	would return 'tech'
trim(' '  from  '   tech   ')	would return 'tech'
trim(leading '0' from '000123')	would return '123'
trim(trailing '1' from 'Tech1')	would return 'Tech'
trim(both '1' from '123Tech111')	would return '23Tech'