Oracle regexp_replace - removing trailing spaces - sql

Question

I am looking for some help in regards to removing trailing spaces from my queue names. The following is an example of a table that I am using:
QUEUE_NAME
Queue A
Queue B
Queue C
The problem I have is that there is an extra space at the end of the queue name and when trying the following code:
SELECT
TRIM(TRAILING ' ' FROM QUEUE_NAME)
FROM
TABLE_QUEUE;
the space is still there.
I was reading the searches from Google and came across the following code to remove special characters [https://community.oracle.com/blogs/bbrumm/2016/12/11/how-to-replace-special-characters-in-oracle-sql] and this removed all the spaces including the one at the end. The code I wrote:
SELECT
REGEXP_REPLACE(QUEUE_NAME, '[^0-9A-Za-z]', '')
FROM
TABLE_QUEUE;
Only issue I have now is that my result is shown as the following:
QUEUE_NAME
QueueA
QueueB
QueueC
I have never really used regexp_replace hence not sure what I need to change to the code to leave the spaces in between the queue names, so would really appreciate it if somebody could advise on how I could fix this.
Thanks in advance.
---- code edited as should not include [.!?]+

Answer 1

You may try to use trim only as in the following select statement :
with t(col0) as
(
select ' Queue A ' from dual union all
select ' Queue B ' from dual union all
select ' Queue C ' from dual
)
select trim(col0)
from t;
trimmedText
-----------
Queue A
Queue B
Queue C
you get no surrounding spaces around.

Answer 2

You want to remove space from the end of the string:
regexp_replace(queue_name, '[[:space:]]+$', '')
(The '$' in the pattern marks the end.)
If this still doesn't work, then you are dealing with some strange invisible character that is not considered space. Use
regexp_replace(queue_name, '[^0-9A-Za-z]+$', '')
instead, which, as you already know, removes all characters except for letters and digits. The '$' restricts this to the end of the string.

Answer 3

Columns of type CHAR (e.g. CHAR(8)) are always blank-padded on the right to the full width of the field. So if you store 'Queue A' in a CHAR(8) field the database helpfully adds a single space to the end of it - and there's no way to remove that extra space from the column. The solution is to change the field so it's defined as either VARCHAR2 (preferred in Oracle) or VARCHAR:
ALTER TABLE TABLE_QUEUE MODIFY QUEUE_NAME VARCHAR2(8);
Then the database will only store the characters you give it, without blank-padding the field.
Best of luck.