diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index c134e7169bfdfd4cc299fe6aaa9d6ec4e9b24950..96f9ce0a14df635bfe5b3e3dd3c4b30cb28617ba 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -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>