To Replace a specific String Pattern in SQL server, create a below function first
CREATE FUNCTION dbo.PatternReplace
(
@InputString VARCHAR(4000),
@Pattern VARCHAR(100),
@ReplaceText VARCHAR(4000)
)
RETURNS VARCHAR(4000)
AS
BEGIN
DECLARE @Result VARCHAR(4000) SET @Result = ''
-- First character in a match
DECLARE @First INT
-- Next character to start search on
DECLARE @Next INT SET @Next = 1
-- Length of the total string -- 8001 if @InputString is NULL
DECLARE @Len INT SET @Len = COALESCE(LEN(@InputString), 8001)
-- End of a pattern
DECLARE @EndPattern INT
WHILE (@Next <= @Len)
BEGIN
SET @First = PATINDEX('%' + @Pattern + '%', SUBSTRING(@InputString, @Next, @Len))
IF COALESCE(@First, 0) = 0 --no match - return
BEGIN
SET @Result = @Result +
CASE --return NULL, just like REPLACE, if inputs are NULL
WHEN @InputString IS NULL
OR @Pattern IS NULL
OR @ReplaceText IS NULL THEN NULL
ELSE SUBSTRING(@InputString, @Next, @Len)
END
BREAK
END
ELSE
BEGIN
-- Concatenate characters before the match to the result
SET @Result = @Result + SUBSTRING(@InputString, @Next, @First - 1)
SET @Next = @Next + @First - 1
SET @EndPattern = 1
-- Find start of end pattern range
WHILE PATINDEX(@Pattern, SUBSTRING(@InputString, @Next, @EndPattern)) = 0
SET @EndPattern = @EndPattern + 1
-- Find end of pattern range
WHILE PATINDEX(@Pattern, SUBSTRING(@InputString, @Next, @EndPattern)) > 0
AND @Len >= (@Next + @EndPattern - 1)
SET @EndPattern = @EndPattern + 1
--Either at the end of the pattern or @Next + @EndPattern = @Len
SET @Result = @Result + @ReplaceText
SET @Next = @Next + @EndPattern - 1
END
END
RETURN(@Result)
END
then try with below
DECLARE @Description NVARCHAR(1000) = '##[2455]## submitted feedback for ##[2794]## project request.'
SELECT REPLACE(dbo.PatternReplace(@Description, '[##0-9##]', ''),'[]','')
