linkend="datatype-datetime">.
</para>
+ <para>
+ In addition, the usual comparison operators shown in
+ <xref linkend="functions-comparison-table"> are available for the
+ date/time types. Dates and timestamps (with or without time zone) are
+ all comparable, while times (with or without time zone) and intervals
+ can only be compared to other values of the same data type. When
+ comparing a timestamp without time zone to a timestamp with time zone,
+ the former value is assumed to be given in the time zone specified by
+ the <xref linkend="guc-timezone"> configuration parameter, and is
+ rotated to UTC for comparison to the latter value (which is already
+ in UTC internally). Similarly, a date value is assumed to represent
+ midnight in the <varname>TimeZone</varname> zone when comparing it
+ to a timestamp.
+ </para>
+
<para>
All the functions and operators described below that take <type>time</type> or <type>timestamp</type>
inputs actually come in two variants: one that takes <type>time with time zone</type> or <type>timestamp