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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
This commit is contained in:
Bruce Momjian 2000-06-20 18:04:18 +00:00
parent bfdb695b85
commit b997a4b91f
3 changed files with 85 additions and 4 deletions
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81
doc/src/sgml/func.sgml
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@ -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

4
doc/src/sgml/sql.sgml
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@ -1,5 +1,5 @@
<!--
$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

4
doc/src/sgml/syntax.sgml
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@ -1,5 +1,5 @@
<!--
$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