Re: [SQL] Mail about typecast

  <p>Vikrant Rathore ha scritto: <blockquote type="CITE">Dear friends, <p>    I want to run a query : <p>vikrant=>
selectdate_part('epoch','12 hours'::timespan)::float4; <br />It returns a error message <br />ERROR:  function
dtof(float8)does not exist <p>But i want to use typecast since the result of this query will be used <br />to update a
fieldof type float4. <p>I have checked the pg_proc system table it has a function dtof with <br />float8 as argument i
havechecked the list of functions also and <br />'dtof(float8)' is shown in that list also. <br />can anyone solve this
problem.I can solve the problem by using a c <br />program but i want to know when the function dtof(float8) is there
in<br />pg_proc table then why it is not doing a typecasting. <br />Thanks in advance for your kind suggestion.
<p>Thanks& regards, <br /><tt>Vikrant.</tt></blockquote><tt>Which version of PostgreSQL are you using?</tt><br
/><tt>Thisworks for me. (v6.5)</tt><tt></tt><p><tt>hygea=> \df dtof</tt><br
/><tt>result|function|arguments|description</tt><br/><tt>------+--------+---------+------------------------</tt><br
/><tt>float4|dtof   |float8   |convert float8 to float4</tt><br /><tt>(1 row)</tt><tt></tt><p><tt>hygea=> select
date_part('epoch','12hours'::timespan)::float4;</tt><br /><tt>float4</tt><br /><tt>------</tt><br /><tt> 43200</tt><br
/><tt>(1row)</tt><tt></tt><p><tt>hygea=> select date_part('epoch','12 hours'::timespan);</tt><br
/><tt>date_part</tt><br/><tt>---------</tt><br /><tt>    43200</tt><br /><tt>(1
row)</tt><tt></tt><p>______________________________________________________________<br />PostgreSQL 6.5.0 on
i586-pc-linux-gnu,compiled by gcc 2.7.2.3 <br />^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ <br
/>Jose'<br />