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| -rw-r--r-- | doc/src/sgml/func.sgml | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 5021ac1ca96..1e044b51a16 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -8191,13 +8191,29 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}'); </para> <para> + In addition, the usual comparison operators shown in + <xref linkend="functions-comparison-op-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 with time zone</type>, and one that takes <type>time without time zone</type> or <type>timestamp without time zone</type>. For brevity, these variants are not shown separately. Also, the <literal>+</literal> and <literal>*</literal> operators come in commutative pairs (for - example both date + integer and integer + date); we show only one of each - such pair. + example both <type>date</type> <literal>+</literal> <type>integer</type> + and <type>integer</type> <literal>+</literal> <type>date</type>); we show + only one of each such pair. </para> <table id="operators-datetime-table"> |