Thanks for answer.

I am not concerning about values per se. Sure, the numbers are random, so values will be different each time I run the query.

My concern is, that I should get each time exactly 3 rows (I am not voried about the content of rows). With CTE I get less or more rows, each time I run the query.

With the real table, the same query returns exactly 3 rows.

Why is the difference between CTE and real table?

Thanks.