Removing duplicate comma seperated values from a datacell in sqlserver

CREATE FUNCTION [dbo].[Split](@String varchar(8000), @Delimiter char(1))
returns @temptable TABLE (items varchar(8000))
as
begin
    declare @idx int
    declare @slice varchar(8000)
 
    select @idx = 1
        if len(@String)<1 or @String is null  return
 
    while @idx!= 0
    begin
        set @idx = charindex(@Delimiter,@String)
        if @idx!=0
            set @slice = left(@String,@idx - 1)
        else
            set @slice = @String
 
        if(len(@slice)>0)
            insert into @temptable(Items) values(@slice)
 
        set @String = right(@String,len(@String) - @idx)
        if len(@String) = 0 break
    end
return
end

select Split('2,3,4',',')

Delete from [tablename] where [id]=[your value]