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 …
Variants: with order by
Similar functions: rank()
, dense_rank()
, percent_rank()
, cume_dist()
.
Product specific forms: rownum
(pseudo column).
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.
You can’t catch up on 20 years of SQL evolution in one day. Subscribe the newsletter via E-Mail, Twitter or RSS to gradually catch up and to keep modern-sql.com on your radar.
The essence of SQL tuning in 200 pages
Buy now!
(paperback and/or PDF)
Paperback also available at Amazon.com.
Markus offers SQL training and consulting for developers working at companies of all sizes.
Learn more »