SQL REPLACE with Multiple [0-9] - sql

Question

I have a string that I want to replace a group of numbers.
The string contains groupings of numbers (and a few letters). 'A12 456 1 65 7944'
I want to replace the group of 3 numbers with 'xxx', and the group of 4 numbers with 'zzzz'
I thought something like REPLACE(#str, '%[0-9][0-9][0-9]%', 'xxx') would work, but it doesn't. I can't even get '%[0-9]%' to replace anything.
If REPLACE is not suitable, how can I replace groups of numbers?

Answer 1

Please try the following solution based on XML and XQuery.
Notable points:
We are tokenizing input string as XML in the CROSS APPLY clause.
XQuery's FLWOR expression is checking for numeric integer values with
a particular length, and substitutes then with a replacement string.
XQuery .value() method outputs back a final result.
SQL
-- DDL and sample data population, start
DECLARE #tbl TABLE (ID INT IDENTITY PRIMARY KEY, tokens VARCHAR(MAX));
INSERT INTO #tbl (tokens) VALUES
('A12 456 1 65 7944');
-- DDL and sample data population, end
DECLARE #separator CHAR(1) = SPACE(1);
SELECT t.*
, c.query('
for $x in /root/r/text()
return if (xs:int($x) instance of xs:int and string-length($x)=3) then "xxx"
else if (xs:int($x) instance of xs:int and string-length($x)=4) then "zzzz"
else data($x)
').value('.', 'VARCHAR(MAX)') AS Result
FROM #tbl AS t
CROSS APPLY (SELECT TRY_CAST('<root><r><![CDATA[' +
REPLACE(tokens, #separator, ']]></r><r><![CDATA[') +
']]></r></root>' AS XML)) AS t1(c);
Output
+----+-------------------+-------------------+
| ID | tokens | Result |
+----+-------------------+-------------------+
| 1 | A12 456 1 65 7944 | A12 xxx 1 65 zzzz |
+----+-------------------+-------------------+