Oracle SQL query to find special characters for phone numbers - sql

Question

I am trying to write a query to find special character for phone numbers.
Expected phone number is : 2047653894
Actual: 204765389(4, 204-7653894, -2047653894, (204)7653894, 20476+53894, ....
NOTE: I only want to find the phone numbers with special characters. I don't want to replace special characters.

Answer 1

Another option is to remove all non-digits (here, where I live, phone numbers are digits only; I'm not talking about various formats phone numbers might have):
SQL> with test (col) as
2 (select '204765389(4' from dual union all
3 select '204-7653894' from dual union all
4 select '-2047653894' from dual union all
5 select '(204)7653894' from dual union all
6 select '20476+53894' from dual
7 )
8 select
9 col,
10 regexp_replace(col, '\D') result
11 from test;
COL RESULT
------------ ------------------------------------------------
204765389(4 2047653894
204-7653894 2047653894
-2047653894 2047653894
(204)7653894 2047653894
20476+53894 2047653894
SQL>
[EDIT]
If you just want to find phone numbers that contain anything but digits, use regexp_like:
SQL> with test (col) as
2 (select '204765389(4' from dual union all
3 select '204-7653894' from dual union all
4 select '-2047653894' from dual union all
5 select '(204)7653894' from dual union all
6 select '20476+53894' from dual union all
7 select '2047653897' from dual
8 )
9 select col
10 from test
11 where regexp_like(col, '\D');
COL
------------
204765389(4
204-7653894
-2047653894
(204)7653894
20476+53894
SQL>

Answer 2

You can use [[:punct:]] posix along with REGEXP_REPLACE() such as
SELECT REGEXP_REPLACE(col,'[[:punct:]]') AS col
FROM t
assuming each comma-separated value represents a column value within a table
Demo

Answer 3

While you can use regular expressions, they are slow and it may be faster to use simple string functions and use TRANSLATE to find all the non-numeric characters and then replace them:
SELECT TRANSLATE(
phone_number,
'0' || TRANSLATE(phone_number, 'x0123456789', 'x')
'0'
) AS simplified_phone_number
FROM table_name;
Which, for your sample data:
CREATE TABLE table_name (phone_number) AS
SELECT '204765389(4' FROM DUAL UNION ALL
SELECT '204-7653894' FROM DUAL UNION ALL
SELECT '-2047653894' FROM DUAL UNION ALL
SELECT '(204)7653894' FROM DUAL UNION ALL
SELECT '20476+53894' FROM DUAL;
Outputs:
SIMPLIFIED_PHONE_NUMBER
2047653894
2047653894
2047653894
2047653894
2047653894
fiddle
Update
If you want to list phone numbers with non-digit characters then you can also use TRANSLATE to remove the digits and check if there are any other characters:
SELECT *
FROM table_name
WHERE TRANSLATE(phone_number, 'x0123456789', 'x') IS NOT NULL
you could also use REGEXP_LIKE to check that the string is not entirely digits:
SELECT *
FROM table_name
WHERE NOT REGEXP_LIKE(phone_number, '^\d+$')
or that there are non-digits:
SELECT *
FROM table_name
WHERE REGEXP_LIKE(phone_number, '\D')
However, regular expressions are probably going to be slower than simple string functions like TRANSLATE.
fiddle