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Add some real descriptions to the multiargument aggregate functions rather

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than just showing the incomprehensible formulas.
This commit is contained in:
Peter Eisentraut 2006-10-23 19:57:37 +00:00
parent 28b14b034a
commit 0ff4352d7a
1 changed files with 33 additions and 65 deletions
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98
doc/src/sgml/func.sgml
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@ -1,4 +1,4 @@
<!-- $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">
<title>Functions and Operators</title>
@ -8102,17 +8102,7 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>sqrt((<replaceable class="parameter">N</replaceable> *
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>
<entry>correlation coefficient</entry>
</row>
<row>
@ -8129,12 +8119,7 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>(sum(<replaceable class="parameter">X</replaceable>*<replaceable
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>
<entry>population covariance</entry>
</row>
<row>
@ -8151,12 +8136,7 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>(sum(<replaceable class="parameter">X</replaceable>*<replaceable
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>
<entry>sample covariance</entry>
</row>
<row>
@ -8169,8 +8149,8 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>sum(<replaceable class="parameter">X</replaceable>) /
<replaceable class="parameter">N</replaceable></entry>
<entry>average of the independent variable
(<literal>sum(<replaceable class="parameter">X</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row>
<row>
@ -8183,8 +8163,8 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>sum(<replaceable class="parameter">Y</replaceable>) /
<replaceable class="parameter">N</replaceable></entry>
<entry>average of the dependent variable
(<literal>sum(<replaceable class="parameter">Y</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row>
<row>
@ -8197,7 +8177,7 @@ SELECT count(*) FROM sometable;
<entry>
<type>bigint</type>
</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>
@ -8213,14 +8193,10 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>(sum(<replaceable class="parameter">Y</replaceable>) *
sum(<replaceable class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>) * sum(<replaceable
class="parameter">X</replaceable>*<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>
<entry>y-intercept of the least-squares-fit linear equation
determined by the (<replaceable
class="parameter">X</replaceable>, <replaceable
class="parameter">Y</replaceable>) pairs</entry>
</row>
<row>
@ -8233,17 +8209,7 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>(<replaceable class="parameter">N</replaceable> *
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>
<entry>square of the correlation coefficient</entry>
</row>
<row>
@ -8259,14 +8225,9 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>(<replaceable class="parameter">N</replaceable> *
sum(<replaceable class="parameter">X</replaceable>*<replaceable
class="parameter">Y</replaceable>) - sum(<replaceable
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>
<entry>slope of the least-squares-fit linear equation determined
by the (<replaceable class="parameter">X</replaceable>,
<replaceable class="parameter">Y</replaceable>) pairs</entry>
</row>
<row>
@ -8279,9 +8240,11 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>sum(<replaceable class="parameter">X</replaceable>^2) -
sum(<replaceable class="parameter">X</replaceable>)^2 / <replaceable
class="parameter">N</replaceable></entry>
<entry><literal>sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2/<replaceable
class="parameter">N</replaceable></literal> (<quote>sum of
squares</quote> of the independent variable)</entry>
</row>
<row>
@ -8294,11 +8257,14 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</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">X</replaceable>) * sum(<replaceable
class="parameter">Y</replaceable>) / <replaceable
class="parameter">N</replaceable></entry>
class="parameter">Y</replaceable>)/<replaceable
class="parameter">N</replaceable></literal> (<quote>sum of
products</quote> of independent times dependent
variable)</entry>
</row>
<row>
@ -8311,9 +8277,11 @@ SELECT count(*) FROM sometable;
<entry>
<type>double precision</type>
</entry>
<entry>sum(<replaceable class="parameter">Y</replaceable>^2) -
sum(<replaceable class="parameter">Y</replaceable>)^2 / <replaceable
class="parameter">N</replaceable></entry>
<entry><literal>sum(<replaceable
class="parameter">Y</replaceable>^2) - sum(<replaceable
class="parameter">Y</replaceable>)^2/<replaceable
class="parameter">N</replaceable></literal> (<quote>sum of
squares</quote> of the dependent variable)</entry>
</row>
<row>