FIND AND REPLACE IN TEXT COLUMN

DECLARE	@oldtext	varchar(1000)
DECLARE @newtext	varchar(1000)
DECLARE @textlen	int
DECLARE @ptr		BINARY(16)
DECLARE @pos		int
DECLARE @id		uniqueidentifier
 
SET @oldtext = 'a'
SET @newtext = 'b'
SET @textlen = LEN(@oldtext)
 
DECLARE mycursor CURSOR LOCAL FAST_FORWARD
FOR
	SELECT	TEXTPTR([Text])
		,CHARINDEX(@oldtext, [Text]) - 1
	FROM	[dbo].[TABLE] 
	WHERE	[Text] LIKE '%' + @oldtext +'%'
 
OPEN mycursor
 
FETCH NEXT FROM mycursor INTO @ptr, @pos
 
WHILE @@fetch_status = 0
BEGIN	
	UPDATETEXT [TABLE].Text @ptr @pos @textlen @newtext
 
	FETCH NEXT FROM mycursor INTO @ptr, @pos	
END
 
CLOSE mycursor
DEALLOCATE mycursor