How can i Identify if a secuence of numbers is wrong

declare @nums varchar(100) = '1,2,3,4,5,6,8,10'

-- first parse the csv string into a temp table
declare @id varchar(20), @start bigint = 0, @end bigint = 0, @rest varchar(max), @sep char(1) = ',';


declare @tabNums table (Num int primary key clustered not null)

	
while 1 = 1
begin	
	set @start = @end + 1;
	set @end = charindex(@sep, @nums, @start)
		
	if @end = 0
		set @id = substring(@nums, @start, len(@nums) - @start + 1);
	else			
		set @id = substring(@nums, @start, @end - @start);
		
	insert
		@tabNums
		(Num)
	values
		(@id)
	;
		
	if @end = 0
		break;
end


-- now check for holes in the chain
declare @num int, @num_before int = -1

declare curNumChain  cursor
	for
		select 
			Num
		from 
			@tabNums
		order by
			Num asc	

open curNumChain ;

Fetch NEXT FROM curNumChain  INTO @num
While (@@FETCH_STATUS <> -1)
begin
	if @num is null
		break;
	
	if @num_before > -1	
		if (@num - @num_before) > 1
		begin
			set @num_before = @num_before + 1
			while @num_before < @num
			begin
				select convert(varchar, @num_before) + ' is missing'
				set @num_before = @num_before + 1
			end
		end
	set @num_before = @num
	Fetch NEXT FROM curNumChain  INTO @num
end
close curNumChain 
deallocate curNumChain