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| author | Bruce Momjian <bruce@momjian.us> | 2003-03-19 21:20:52 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2003-03-19 21:20:52 +0000 |
| commit | 1ef7ba20e774bd8f94a9642db22585c5b9aa3aa7 (patch) | |
| tree | 8b58bafd950dea6604cd77849104d92bf13a800e | |
| parent | 8cb041aadad10e423570b54e71c6237a86c84d95 (diff) | |
| download | postgresql-1ef7ba20e774bd8f94a9642db22585c5b9aa3aa7.tar.gz postgresql-1ef7ba20e774bd8f94a9642db22585c5b9aa3aa7.zip | |
Remove typecasting section that isn't needed anymore.
| -rw-r--r-- | doc/src/sgml/typeconv.sgml | 53 |
1 files changed, 1 insertions, 52 deletions
diff --git a/doc/src/sgml/typeconv.sgml b/doc/src/sgml/typeconv.sgml index d049451e68b..f17e2e5c9a3 100644 --- a/doc/src/sgml/typeconv.sgml +++ b/doc/src/sgml/typeconv.sgml @@ -1,5 +1,5 @@ <!-- -$Header: /cvsroot/pgsql/doc/src/sgml/typeconv.sgml,v 1.27 2003/03/13 01:30:29 petere Exp $ +$Header: /cvsroot/pgsql/doc/src/sgml/typeconv.sgml,v 1.28 2003/03/19 21:20:52 momjian Exp $ --> <chapter Id="typeconv"> @@ -403,57 +403,6 @@ type to resolve the unknown literals to. </para> </example> -<example> -<title>Absolute-Value and Factorial Operator Type Resolution</title> - -<para> -The <productname>PostgreSQL</productname> operator catalog has several -entries for the prefix operator <literal>@</>, all of which implement -absolute-value operations for various numeric data types. One of these -entries is for type <type>float8</type>, which is the preferred type in -the numeric category. Therefore, <productname>PostgreSQL</productname> -will use that entry when faced with a non-numeric input: -<screen> -SELECT @ '-4.5' AS "abs"; - abs ------ - 4.5 -(1 row) -</screen> -Here the system has performed an implicit conversion from <type>text</type> to <type>float8</type> -before applying the chosen operator. We can verify that <type>float8</type> and -not some other type was used: -<screen> -SELECT @ '-4.5e500' AS "abs"; - -ERROR: Input '-4.5e500' is out of range for float8 -</screen> -</para> - -<para> -On the other hand, the postfix operator <literal>!</> (factorial) -is defined only for integer data types, not for <type>float8</type>. So, if we -try a similar case with <literal>!</>, we get: -<screen> -SELECT '20' ! AS "factorial"; - -ERROR: Unable to identify a postfix operator '!' for type 'text' - You may need to add parentheses or an explicit cast -</screen> -This happens because the system can't decide which of the several -possible <literal>!</> operators should be preferred. We can help -it out with an explicit cast: -<screen> -SELECT CAST('20' AS int8) ! AS "factorial"; - - factorial ---------------------- - 2432902008176640000 -(1 row) -</screen> -</para> -</example> - </sect1> <sect1 id="typeconv-func"> |