Home • Explore • Blog • CI
☰



postgresql
29th chunk of `doc/src/sgml/ecpg.sgml`
d57e03e588372ad2029d4abfc0efd5612d8082e52be2b2f50000000100000fa0
 <row>
            <entry><literal>08-Jan-06</literal></entry>
            <entry><literal>January 8, 2006</literal></entry>
           </row>
           <row>
            <entry><literal>Jan-08-99</literal></entry>
            <entry><literal>January 8, 1999</literal></entry>
           </row>
           <row>
            <entry><literal>19990108</literal></entry>
            <entry><literal>ISO 8601; January 8, 1999</literal></entry>
           </row>
           <row>
            <entry><literal>990108</literal></entry>
            <entry><literal>ISO 8601; January 8, 1999</literal></entry>
           </row>
           <row>
            <entry><literal>1999.008</literal></entry>
            <entry><literal>year and day of year</literal></entry>
           </row>
           <row>
            <entry><literal>J2451187</literal></entry>
            <entry><literal>Julian day</literal></entry>
           </row>
           <row>
            <entry><literal>January 8, 99 BC</literal></entry>
            <entry><literal>year 99 before the Common Era</literal></entry>
           </row>
          </tbody>
         </tgroup>
        </table>
      </listitem>
     </varlistentry>

     <varlistentry id="pgtypesdatetoasc">
      <term><function>PGTYPESdate_to_asc</function></term>
      <listitem>
       <para>
        Return the textual representation of a date variable.
<synopsis>
char *PGTYPESdate_to_asc(date dDate);
</synopsis>
        The function receives the date <literal>dDate</literal> as its only parameter.
        It will output the date in the form <literal>1999-01-18</literal>, i.e., in the
        <literal>YYYY-MM-DD</literal> format.
        The result must be freed with <function>PGTYPESchar_free()</function>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="pgtypesdatejulmdy">
      <term><function>PGTYPESdate_julmdy</function></term>
      <listitem>
       <para>
        Extract the values for the day, the month and the year from a variable
        of type date.
<synopsis>
void PGTYPESdate_julmdy(date d, int *mdy);
</synopsis>
       <!-- almost same description as for rjulmdy() -->
        The function receives the date <literal>d</literal> and a pointer to an array
        of 3 integer values <literal>mdy</literal>. The variable name indicates
        the sequential order: <literal>mdy[0]</literal> will be set to contain the
        number of the month, <literal>mdy[1]</literal> will be set to the value of the
        day and <literal>mdy[2]</literal> will contain the year.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="pgtypesdatemdyjul">
      <term><function>PGTYPESdate_mdyjul</function></term>
      <listitem>
       <para>
        Create a date value from an array of 3 integers that specify the
        day, the month and the year of the date.
<synopsis>
void PGTYPESdate_mdyjul(int *mdy, date *jdate);
</synopsis>
        The function receives the array of the 3 integers (<literal>mdy</literal>) as
        its first argument and as its second argument a pointer to a variable
        of type date that should hold the result of the operation.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry id="pgtypesdatedayofweek">
      <term><function>PGTYPESdate_dayofweek</function></term>
      <listitem>
       <para>
        Return a number representing the day of the week for a date value.
<synopsis>
int PGTYPESdate_dayofweek(date d);
</synopsis>
        The function receives the date variable <literal>d</literal> as its only
        argument and returns an integer that indicates the day of the week for
        this date.
        <itemizedlist>
         <listitem>
          <para>
           0 - Sunday
          </para>
         </listitem>
         <listitem>
          <para>
           1 - Monday
          </para>
         </listitem>
         <listitem>
          <para>
           2 - Tuesday
          </para>
         </listitem>
Title: pgtypes Library: Date Conversion Functions
Summary
This section describes several functions in the pgtypes library for handling date conversions. It covers `PGTYPESdate_to_asc`, which converts a date variable to a string in YYYY-MM-DD format, and whose result must be freed using `PGTYPESchar_free()`. It also describes `PGTYPESdate_julmdy`, which extracts the day, month, and year from a date variable into an integer array. The section further includes `PGTYPESdate_mdyjul`, which creates a date value from an array of integers representing the day, month, and year. Finally, `PGTYPESdate_dayofweek` is detailed, which returns an integer representing the day of the week for a given date.