If your query doesn’t have an ORDER BY clause,
you can’t reliably predict the order of your results over time.
Sure, it’s going to look predictable at first, but down the road, as things change – the indexes, the table, the server’s configuration, the size of your data – you can end up with some ugly surprises.
Let’s start with something simple: we’ll do a SELECT from the Stack Overflow Users table. The clustering key on that table is Id, the identity number that starts at one and goes up to a bajillion. When we do this SELECT, the data comes