Skip to content
Snippets Groups Projects
Commit b997a4b9 authored by Bruce Momjian's avatar Bruce Momjian
Browse files

> Great! Please cc: the docs or hackers mailing lists to make sure the

> patches are not lost...

Aggregate doc patches:

The patches are attached. Be great if you could check them over to make
sure all relevant content (and markup) is there...

Isaac Wilcox
parent bfdb695b
No related branches found
No related tags found
No related merge requests found
......@@ -1515,6 +1515,87 @@ Not defined by this name. Implements the intersection operator '#'
</sect1>
<sect1>
<title id="aggregate-funcs">Aggregate Functions</title>
<note>
<title>Author</title>
<para>
Written by <ulink url="mailto:isaac@azartmedia.com">Isaac Wilcox</ulink>
on 2000-06-16.
</para>
</note>
<para>
<firstterm>Aggregate functions</firstterm> allow the generation of simple
statistics about the values of particular columns over the selected set
of rows. See also <xref linkend="sql" endterm="aggregates-tutorial"> and
<xref linkend="syntax" endterm="aggregates-syntax">.
</para>
<para>
<table tocentry="1">
<title>Aggregate Functions</title>
<tgroup cols="4">
<thead>
<row>
<entry>Function</entry>
<entry>Returns</entry>
<entry>Description</entry>
<entry>Example</entry>
<entry>Notes</entry>
</row>
</thead>
<tbody>
<row>
<entry>COUNT(*)</entry>
<entry>int4</entry>
<entry>Counts the selected rows.</entry>
<entry>COUNT(*)</entry>
<entry></entry>
</row>
<row>
<entry>COUNT(<replaceable class="parameter">column-name</replaceable>)</entry>
<entry>int4</entry>
<entry>Counts the selected rows for which the value of <replaceable class="parameter">column-name</replaceable> is not NULL.</entry>
<entry>COUNT(age)</entry>
<entry></entry>
</row>
<row>
<entry>SUM(<replaceable class="parameter">column-name</replaceable>)</entry>
<entry>Same as the data type of the column being summed.</entry>
<entry>Finds the total obtained by adding the values of <replaceable class="parameter">column-name</replaceable> across all selected rows.</entry>
<entry>SUM(hours)</entry>
<entry>Summation is supported on the following data types: int8, int4, int2, float4, float8, money, interval, numeric</entry>
</row>
<row>
<entry>MAX(<replaceable class="parameter">column-name</replaceable>)</entry>
<entry>Same as the data type of the column whose maximum value is sought.</entry>
<entry>The maximum value of <replaceable class="parameter">column-name</replaceable> across all selected rows.</entry>
<entry>MAX(age)</entry>
<entry>Finding the maximum value is supported on the following data types: int8, int4, int2, float4, float8, date, time, timetz, money, timestamp, interval, text, numeric.</entry>
</row>
<row>
<entry>MIN(<replaceable class="parameter">column-name</replaceable>)</entry>
<entry>same as the data type of the column whose minimum value is sought.</entry>
<entry>The minimum value of <replaceable class="parameter">column-name</replaceable> across all selected rows.</entry>
<entry>MIN(age)</entry>
<entry>Finding the minimum value is supported on the following data types: int8, int4, int2, float4, float8, date, time, timetz, money, timestamp, interval, text, numeric.</entry>
</row>
<row>
<entry>AVG(<replaceable class="parameter">column-name</replaceable>)</entry>
<entry>Same as the data type of the column being averaged.</entry>
<entry>The average (mean) of the values in the given column across all selected rows.</entry>
<entry>AVG(age)</entry>
<entry>Finding the mean value is supported on the following data types: int8, int4, int2, float4, float8, money, interval, numeric. Note that as the return type is the same as that of the data being averaged, using AVG() on discrete data will give a rounded result.</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
</sect1>
</chapter>
<!-- Keep this comment at the end of the file
......
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.10 2000/06/14 13:10:48 thomas Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.11 2000/06/20 18:04:18 momjian Exp $
-->
<chapter id="sql">
......@@ -1032,7 +1032,7 @@ SELECT S.SNAME, P.PNAME
</sect3>
<sect3>
<title>Aggregate Operators</title>
<title id="aggregates-tutorial">Aggregate Operators</title>
<para>
<acronym>SQL</acronym> provides aggregate operators
......
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.21 2000/06/09 01:43:56 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.22 2000/06/20 18:04:18 momjian Exp $
-->
<chapter id="syntax">
......@@ -747,7 +747,7 @@ sqrt(emp.salary)
</sect2>
<sect2>
<title>Aggregate Expressions</title>
<title id="aggregates-syntax">Aggregate Expressions</title>
<para>
An <firstterm>aggregate expression</firstterm> represents the application
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment