Commit 0ff4352d authored by Peter Eisentraut's avatar Peter Eisentraut

Add some real descriptions to the multiargument aggregate functions rather

than just showing the incomprehensible formulas.
parent 28b14b03
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.344 2006/10/23 18:10:31 petere Exp $ --> <!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.345 2006/10/23 19:57:37 petere Exp $ -->
<chapter id="functions"> <chapter id="functions">
<title>Functions and Operators</title> <title>Functions and Operators</title>
...@@ -8102,17 +8102,7 @@ SELECT count(*) FROM sometable; ...@@ -8102,17 +8102,7 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sqrt((<replaceable class="parameter">N</replaceable> * <entry>correlation coefficient</entry>
sum(<replaceable class="parameter">X</replaceable>*<replaceable
class="parameter">Y</replaceable>) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>))^2 / ((<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2) * (<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">Y</replaceable>^2) - sum(<replaceable
class="parameter">Y</replaceable>)^2)))</entry>
</row> </row>
<row> <row>
...@@ -8129,12 +8119,7 @@ SELECT count(*) FROM sometable; ...@@ -8129,12 +8119,7 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>(sum(<replaceable class="parameter">X</replaceable>*<replaceable <entry>population covariance</entry>
class="parameter">Y</replaceable>) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>) / <replaceable
class="parameter">N</replaceable>) / <replaceable
class="parameter">N</replaceable></entry>
</row> </row>
<row> <row>
...@@ -8151,12 +8136,7 @@ SELECT count(*) FROM sometable; ...@@ -8151,12 +8136,7 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>(sum(<replaceable class="parameter">X</replaceable>*<replaceable <entry>sample covariance</entry>
class="parameter">Y</replaceable>) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>) / <replaceable
class="parameter">N</replaceable>) / (<replaceable
class="parameter">N</replaceable> - 1)</entry>
</row> </row>
<row> <row>
...@@ -8169,8 +8149,8 @@ SELECT count(*) FROM sometable; ...@@ -8169,8 +8149,8 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sum(<replaceable class="parameter">X</replaceable>) / <entry>average of the independent variable
<replaceable class="parameter">N</replaceable></entry> (<literal>sum(<replaceable class="parameter">X</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row> </row>
<row> <row>
...@@ -8183,8 +8163,8 @@ SELECT count(*) FROM sometable; ...@@ -8183,8 +8163,8 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sum(<replaceable class="parameter">Y</replaceable>) / <entry>average of the dependent variable
<replaceable class="parameter">N</replaceable></entry> (<literal>sum(<replaceable class="parameter">Y</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row> </row>
<row> <row>
...@@ -8197,7 +8177,7 @@ SELECT count(*) FROM sometable; ...@@ -8197,7 +8177,7 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>bigint</type> <type>bigint</type>
</entry> </entry>
<entry>number of input rows in which both expressions are non-null</entry> <entry>number of input rows in which both expressions are nonnull</entry>
</row> </row>
<row> <row>
...@@ -8213,14 +8193,10 @@ SELECT count(*) FROM sometable; ...@@ -8213,14 +8193,10 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>(sum(<replaceable class="parameter">Y</replaceable>) * <entry>y-intercept of the least-squares-fit linear equation
sum(<replaceable class="parameter">X</replaceable>^2) - sum(<replaceable determined by the (<replaceable
class="parameter">X</replaceable>) * sum(<replaceable class="parameter">X</replaceable>, <replaceable
class="parameter">X</replaceable>*<replaceable class="parameter">Y</replaceable>) pairs</entry>
class="parameter">Y</replaceable>)) / (<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2)</entry>
</row> </row>
<row> <row>
...@@ -8233,17 +8209,7 @@ SELECT count(*) FROM sometable; ...@@ -8233,17 +8209,7 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>(<replaceable class="parameter">N</replaceable> * <entry>square of the correlation coefficient</entry>
sum(<replaceable class="parameter">X</replaceable>*<replaceable
class="parameter">Y</replaceable>) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>))^2 / ((<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2) * (<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">Y</replaceable>^2) - sum(<replaceable
class="parameter">Y</replaceable>)^2))</entry>
</row> </row>
<row> <row>
...@@ -8259,14 +8225,9 @@ SELECT count(*) FROM sometable; ...@@ -8259,14 +8225,9 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>(<replaceable class="parameter">N</replaceable> * <entry>slope of the least-squares-fit linear equation determined
sum(<replaceable class="parameter">X</replaceable>*<replaceable by the (<replaceable class="parameter">X</replaceable>,
class="parameter">Y</replaceable>) - sum(<replaceable <replaceable class="parameter">Y</replaceable>) pairs</entry>
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>)) / (<replaceable
class="parameter">N</replaceable> * sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2)</entry>
</row> </row>
<row> <row>
...@@ -8279,9 +8240,11 @@ SELECT count(*) FROM sometable; ...@@ -8279,9 +8240,11 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sum(<replaceable class="parameter">X</replaceable>^2) - <entry><literal>sum(<replaceable
sum(<replaceable class="parameter">X</replaceable>)^2 / <replaceable class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">N</replaceable></entry> class="parameter">X</replaceable>)^2/<replaceable
class="parameter">N</replaceable></literal> (<quote>sum of
squares</quote> of the independent variable)</entry>
</row> </row>
<row> <row>
...@@ -8294,11 +8257,14 @@ SELECT count(*) FROM sometable; ...@@ -8294,11 +8257,14 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sum(<replaceable class="parameter">X</replaceable>*<replaceable <entry><literal>sum(<replaceable
class="parameter">X</replaceable>*<replaceable
class="parameter">Y</replaceable>) - sum(<replaceable class="parameter">Y</replaceable>) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>) / <replaceable class="parameter">Y</replaceable>)/<replaceable
class="parameter">N</replaceable></entry> class="parameter">N</replaceable></literal> (<quote>sum of
products</quote> of independent times dependent
variable)</entry>
</row> </row>
<row> <row>
...@@ -8311,9 +8277,11 @@ SELECT count(*) FROM sometable; ...@@ -8311,9 +8277,11 @@ SELECT count(*) FROM sometable;
<entry> <entry>
<type>double precision</type> <type>double precision</type>
</entry> </entry>
<entry>sum(<replaceable class="parameter">Y</replaceable>^2) - <entry><literal>sum(<replaceable
sum(<replaceable class="parameter">Y</replaceable>)^2 / <replaceable class="parameter">Y</replaceable>^2) - sum(<replaceable
class="parameter">N</replaceable></entry> class="parameter">Y</replaceable>)^2/<replaceable
class="parameter">N</replaceable></literal> (<quote>sum of
squares</quote> of the dependent variable)</entry>
</row> </row>
<row> <row>
......
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