Can I use… row_number() (without order by)

The row_number() window function can be used without order by in over to arbitrarily assign a unique value to each row.

SELECT ROW_NUMBER() OVER ()
  FROM …

Related

• Variants: with order by

• Similar functions: rank(), dense_rank(), percent_rank(), cume_dist().

• Product specific forms: rownum (pseudo column).

Normative References

The row_number() window function is defined in ISO/IEC 9075:2016-2 as part of optional feature T611, “Elementary OLAP operations”. Using row_number() without order by is part of optional feature T612.