Add additional example for interval multiplication.

Fix example for day and hours interval subtraction for new computation
method.

Update interval examples to display zero seconds, which is our default.

Backpatch to 8.1.X.

doc/src/sgml/func.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.298 2005/12/11 10:54:27 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.299 2005/12/21 16:02:24 momjian Exp $
 PostgreSQL documentation
 -->
 
@@ -5120,37 +5120,37 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
        <row>
         <entry> <literal>+</literal> </entry>
         <entry><literal>date '2001-09-28' + interval '1 hour'</literal></entry>
-        <entry><literal>timestamp '2001-09-28 01:00'</literal></entry>
+        <entry><literal>timestamp '2001-09-28 01:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>+</literal> </entry>
         <entry><literal>date '2001-09-28' + time '03:00'</literal></entry>
-        <entry><literal>timestamp '2001-09-28 03:00'</literal></entry>
+        <entry><literal>timestamp '2001-09-28 03:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>+</literal> </entry>
         <entry><literal>interval '1 day' + interval '1 hour'</literal></entry>
-        <entry><literal>interval '1 day 01:00'</literal></entry>
+        <entry><literal>interval '1 day 01:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>+</literal> </entry>
         <entry><literal>timestamp '2001-09-28 01:00' + interval '23 hours'</literal></entry>
-        <entry><literal>timestamp '2001-09-29 00:00'</literal></entry>
+        <entry><literal>timestamp '2001-09-29 00:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>+</literal> </entry>
         <entry><literal>time '01:00' + interval '3 hours'</literal></entry>
-        <entry><literal>time '04:00'</literal></entry>
+        <entry><literal>time '04:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>- interval '23 hours'</literal></entry>
-        <entry><literal>interval '-23:00'</literal></entry>
+        <entry><literal>interval '-23:00:00'</literal></entry>
        </row>
 
        <row>
@@ -5168,49 +5168,55 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>date '2001-09-28' - interval '1 hour'</literal></entry>
-        <entry><literal>timestamp '2001-09-27 23:00'</literal></entry>
+        <entry><literal>timestamp '2001-09-27 23:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>time '05:00' - time '03:00'</literal></entry>
-        <entry><literal>interval '02:00'</literal></entry>
+        <entry><literal>interval '02:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>time '05:00' - interval '2 hours'</literal></entry>
-        <entry><literal>time '03:00'</literal></entry>
+        <entry><literal>time '03:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>timestamp '2001-09-28 23:00' - interval '23 hours'</literal></entry>
-        <entry><literal>timestamp '2001-09-28 00:00'</literal></entry>
+        <entry><literal>timestamp '2001-09-28 00:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>interval '1 day' - interval '1 hour'</literal></entry>
-        <entry><literal>interval '23:00'</literal></entry>
+        <entry><literal>interval '1 day -01:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>-</literal> </entry>
         <entry><literal>timestamp '2001-09-29 03:00' - timestamp '2001-09-27 12:00'</literal></entry>
-        <entry><literal>interval '1 day 15:00'</literal></entry>
+        <entry><literal>interval '1 day 15:00:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>*</literal> </entry>
-        <entry><literal>interval '1 hour' * double precision '3.5'</literal></entry>
-        <entry><literal>interval '03:30'</literal></entry>
+        <entry><literal>900 * interval '1 second'</literal></entry>
+        <entry><literal>interval '00:15:00'</literal></entry>
+       </row>
+
+       <row>
+        <entry> <literal>*</literal> </entry>
+        <entry><literal>double precision '3.5' * interval '1 hour'</literal></entry>
+        <entry><literal>interval '03:30:00'</literal></entry>
        </row>
 
        <row>
         <entry> <literal>/</literal> </entry>
         <entry><literal>interval '1 hour' / double precision '1.5'</literal></entry>
-        <entry><literal>interval '00:40'</literal></entry>
+        <entry><literal>interval '00:40:00'</literal></entry>
        </row>
       </tbody>
      </tgroup>