Select (SQL): Difference between revisions

Revision as of 20:59, 25 January 2025

Latest revision as of 05:24, 13 August 2025

(One intermediate revision by the same user not shown)

Line 259:

<code>ROW_NUMBER() OVER</code> may be used for a ''simple table'' on the returned rows, e.g. to return no more than ten rows:

<syntaxhighlight lang="sqltsql" highlight="3">

SELECT * FROM

( SELECT

Line 270:

</syntaxhighlight>

{{mono|ROW_NUMBER}} can be [[Nondeterministic algorithm|non-deterministic]]: if ''sort_key'' is not unique, each time you run the query it is possible to get different row numbers assigned to any rows where ''sort_key'' is the same. When ''sort_key'' is unique, each row will always get a unique row number.

=== RANK() window function ===

The <code>RANK() OVER</code> window function acts like {{mono|ROW_NUMBER}}, but may return more or less than ''n'' rows in case of tie conditions, e.g. to return the top-10 youngest persons:

<syntaxhighlight lang="sqltsql" highlight="3">

SELECT * FROM (

SELECT