SQL Server 2022

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CREATE TABLE TableName (
  Id int identity(1,1) ,
  DelimitedValues varchar(100)
);

INSERT INTO TableName (DelimitedValues) VALUES
('1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15'), 
('2, 3, 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15'), 
('1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15');
3 rows affected

UPDATE TableName
SET DelimitedValues = TRIM(', ' FROM REPLACE(', '+ DelimitedValues +', ', ', 1, ', ', '))
WHERE Id < 3;
2 rows affected

SELECT Id, DelimitedValues
FROM TableName


Id
DelimitedValues


1
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

2
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

3
1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

Id	DelimitedValues
1	2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
2	2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
3	1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15