Trim Whitespaces (New Line and Tab space) in a String in Oracle

Question

I need to trim New Line (Chr(13) and Chr(10) and Tab space from the beginning and end of a String) in an Oracle query. I learnt that there is no easy way to trim multiple characters in Oracle. "trim" function trims only single character. It would be a performance degradation if i call trim function recursivelly in a loop using a function. I heard regexp_replace can match the whitespaces and remove them. Can you guide of a reliable way to use regexp_replace to trim multiple tabspaces or new lines or combinations of them in beginning and end of a String. If there is any other way, Please guide me.

Answer 1

How about the quick and dirty translate function?

This will remove all occurrences of each character in string1:

SELECT translate(
           translate(
               translate(string1, CHR(10), '')
           , CHR(13), '')
       , CHR(09), '') as massaged
FROM BLAH;

Regexp_replace is an option, but you may see a performance hit depending on how complex your expression is.

Answer 2

If you have Oracle 10g, REGEXP_REPLACE is pretty flexible.

Using the following string as a test:

chr(9) || 'Q   qwer' || chr(9) || chr(10) ||
chr(13) || 'qwerqwer     qwerty' || chr(9) || 
chr(10) || chr(13)

The [[:space:]] will remove all whitespace, and the ([[:cntrl:]])|(^\t) regexp will remove non-printing characters and tabs.

select
    tester,
    regexp_replace(tester, '(^[[:space:]]+)|([[:space:]]+$)',null)
            regexp_tester_1,
    regexp_replace(tester, '(^[[:cntrl:]^\t]+)|([[:cntrl:]^\t]+$)',null) 
            regexp_tester_2
from
    (
    select
        chr(9) || 'Q   qwer' || chr(9) || chr(10) ||
                chr(13) || 'qwerqwer     qwerty' || chr(9) || 
                chr(10) || chr(13) tester 
    from 
        dual
    )

Returning:

• REGEXP_TESTER_1: "Qqwerqwerqwerqwerty"
• REGEXP_TESTER_2: "Q qwerqwerqwer qwerty"

Hope this is of some use.

Answer 3

This how I would implement it:

     REGEXP_REPLACE(text,'(^[[:space:]]*|[[:space:]]*$)')

Answer 4

You could use both LTRIM and RTRIM.

select rtrim(ltrim('abcdab','ab'),'ab') from dual;

If you want to trim CHR(13) only when it comes with a CHR(10) it gets more complicated. Firstly, translated the combined string to a single character. Then LTRIM/RTRIM that character, then replace the single character back to the combined string.

select replace(rtrim(ltrim(replace('abccccabcccaab','ab','#'),'#'),'#'),'#','ab') from dual;

Answer 5

TRANSLATE (column_name, 'd'||CHR(10)||CHR(13), 'd')

The 'd' is a dummy character, because translate does not work if the 3rd parameter is null.

Answer 6

For what version of Oracle? 10g+ supports regexes - see this thread on the OTN Discussion forum for how to use REGEXP_REPLACE to change non-printable characters into ''.

Answer 7

I know this is not a strict answer for this question, but I've been working in several scenarios where you need to transform text data following these rules:

1. No spaces or ctrl chars at the beginning of the string
2. No spaces or ctrl chars at the end of the string
3. Multiple ocurrencies of spaces or ctrl chars will be replaced to a single space

Code below follow the rules detailed above:

WITH test_view AS (
  SELECT CHR(9) || 'Q   qwer' || CHR(9) || CHR(10) ||
         CHR(13) || ' qwerqwer     qwerty  ' || CHR(9) || 
         CHR(10) || CHR(13) str
  FROM DUAL
) SELECT 
     str original
    ,TRIM(REGEXP_REPLACE(str, '([[:space:]]{2,}|[[:cntrl:]])', ' ')) fixed
  FROM test_view;


ORIGINAL               FIXED                 
---------------------- ----------------------
    Q   qwer           Q qwer qwerqwer qwerty

 qwerqwer     qwerty                                         

1 row selected.

Answer 8

In cases where the Oracle solution seems overly convoluted, I create a java class with static methods and then install it as a package in Oracle. This might not be as performant, but you will eventually find other cases (date conversion to milliseconds for example) where you will find the java fallback helpful.

Answer 9

Below code can be used to Remove New Line and Table Space in text column

Select replace(replace(TEXT,char(10),''),char(13),'')

Answer 10

Try the code below. It will work if you enter multiple lines in a single column.

create table  products (prod_id number , prod_desc varchar2(50));

insert into products values(1,'test first

test second

test third');

select replace(replace(prod_desc,chr(10),' '),chr(13),' ') from products  where prod_id=2; 

Output :test first test second test third

Answer 11

TRIM(BOTH chr(13)||chr(10)||' ' FROM str)

Answer 12

Instead of using regexp_replace multiple time use (\s) as given below;

SELECT regexp_replace('TEXT','(\s)','')
FROM dual;