Can I depend on order of output when using row_number()

Question

I believe the answer is no. And am looking for a counter example to show that order of output is not guaranteed, absent an order by clause.

Answer 1

As mentioned, you can't rely on row order without an ORDER BY.

However, you can rely on the ROW_NUMBER() function value.

SELECT
    principal_id, name, 
    ROW_NUMBER() OVER (ORDER BY principal_id DESC) AS DemoRank
FROM
    msdb.sys.database_principals
ORDER BY
    name

If you consume the data in your client by DemoRank, then you would be OK, even without the ORDER BY clause

If you rely on recordset ordering (ordinal index), then no.

The example above gives first row (index = 0) as '##MS_PolicyEventProcessingLogin##', but using DemoRank value gives "db_denydatawriter"

Basically, use ORDER BY.