current_timestamp.sgml

关系型数据库 Postgresql 6.5.2

<REFENTRY ID="SQL-CURRENT-TIMESTAMP">
 <REFMETA>
  <REFENTRYTITLE>
   SQL_CURRENT_TIMESTAMP
  </REFENTRYTITLE>
  <REFMISCINFO>SQL - Functions</REFMISCINFO>
 </REFMETA>
 <REFNAMEDIV>
  <REFNAME>
   CURRENT_TIMESTAMP
  </REFNAME>
  <REFPURPOSE>
   Returns the current date and time
  </REFPURPOSE>
  
  
 <REFSYNOPSISDIV>
  <REFSYNOPSISDIVINFO>
   <DATE>1998-04-15</DATE>
  </REFSYNOPSISDIVINFO>
  <synopsis>
  CURRENT_TIMESTAMP 
 </SYNOPSIS>
  
  <REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-1">
   <REFSECT2INFO>
    <DATE>1998-04-15</DATE>
   </REFSECT2INFO>
   <TITLE>
    Inputs
   </TITLE>
   <PARA>
None.

  </REFSECT2>
  
  <REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-2">
   <REFSECT2INFO>
    <DATE>1998-04-15</DATE>
   </REFSECT2INFO>
   <TITLE>
    Outputs
   </TITLE>
   <PARA>
       <VARIABLELIST>
	<VARLISTENTRY>
	 <TERM>
<replaceable>timestamp</replaceable>

	 <LISTITEM>
	  <PARA>
	  Returns "<replaceable class="parameter">today</replaceable>" and "<replaceable class="parameter">now</replaceable>".

   </VARIABLELIST>
  </REFSECT2>
 </REFSYNOPSISDIV>
 
 <REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-1">
  <REFSECT1INFO>
   <DATE>1998-04-15</DATE>
  </REFSECT1INFO>
  <TITLE>
   Description
  </TITLE>
  <PARA>
   The niladic CURRENT_TIMESTAMP function has a data type of
   TIMESTAMP and returns the date and local time at which it is run.
  </PARA>
  
  <REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-3">
   <REFSECT2INFO>
    <DATE>1998-04-15</DATE>
   </REFSECT2INFO>
   <TITLE>
    Notes
   </TITLE>
   <PARA>
    Refer to the SET TIME ZONE statement for a further description
    of local time.
   </PARA>
   
   
  </REFSECT2>
  
 <REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-2">
  <TITLE>
   Usage
  </TITLE>
  <PARA>
   Display CURRENT_TIMESTAMP:
  </PARA>
  <ProgramListing>
   SELECT CURRENT_TIMESTAMP AS date_and_time;

   date_and_time
   ----------------------
   1998-03-31 07:41:21-08
  </ProgramListing>
 </REFSECT1>
 
 <REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-3">
  <TITLE>
   Compatibility
  </TITLE>
  <PARA>
  </PARA>
  
  <REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-4">
   <REFSECT2INFO>
    <DATE>1998-04-15</DATE>
   </REFSECT2INFO>
   <TITLE>
    SQL92
   </TITLE>
   <PARA>
   SQL92 specifies some additional capabilities for CURRENT_TIMESTAMP:
   </PARA>
   
   <VARIABLELIST>
    <VARLISTENTRY>
     <TERM>
     </TERM>
     <LISTITEM>
      <PARA>
       <VARIABLELIST>
	<VARLISTENTRY>
	 <TERM>
	  <ReturnValue>CURRENT_TIMESTAMP [ (<replaceable class="parameter">scale</replaceable>) ]</ReturnValue>
	 </TERM>
	 <LISTITEM>
	  <PARA>
	   The optional scale for CURRENT_TIMESTAMP, if specified, is an
	   unsigned integer representing the number of digits in the
	   optional seconds fraction of the time value represented
	   by the function.
	  </PARA>
	 </LISTITEM>
	</VARLISTENTRY>
       </VARIABLELIST>
      </para>
     </LISTITEM>
    </VARLISTENTRY>
   </VARIABLELIST>
  </refsect2>
 </refsect1>
</REFENTRY>

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