diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/filelist.sgml | 2 | ||||
| -rw-r--r-- | doc/src/sgml/func.sgml | 73 |
2 files changed, 44 insertions, 31 deletions
diff --git a/doc/src/sgml/filelist.sgml b/doc/src/sgml/filelist.sgml index fb69415f800..7a698e59b3e 100644 --- a/doc/src/sgml/filelist.sgml +++ b/doc/src/sgml/filelist.sgml @@ -25,7 +25,7 @@ <!ENTITY mvcc SYSTEM "mvcc.sgml"> <!ENTITY perform SYSTEM "perform.sgml"> <!ENTITY queries SYSTEM "queries.sgml"> -<!entity rangetypes SYSTEM "rangetypes.sgml"> +<!ENTITY rangetypes SYSTEM "rangetypes.sgml"> <!ENTITY rowtypes SYSTEM "rowtypes.sgml"> <!ENTITY syntax SYSTEM "syntax.sgml"> <!ENTITY textsearch SYSTEM "textsearch.sgml"> diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 7ecf7510435..b9ef827984d 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -10461,6 +10461,10 @@ SELECT NULLIF(value, '(none)') ... <title>Range Functions and Operators</title> <para> + See <xref linkend="rangetypes"> for an overview of range types. + </para> + + <para> <xref linkend="range-operators-table"> shows the operators available for range types. </para> @@ -10556,65 +10560,74 @@ SELECT NULLIF(value, '(none)') ... <row> <entry> <literal>&<</literal> </entry> - <entry>Does not extend to the right of?</entry> + <entry>does not extend to the right of</entry> <entry><literal>int8range(1,20) &< int8range(18,20)</literal></entry> <entry><literal>t</literal></entry> </row> <row> <entry> <literal>&></literal> </entry> - <entry>Does not extend to the left of?</entry> + <entry>does not extend to the left of</entry> <entry><literal>int8range(7,20) &> int8range(5,10)</literal></entry> <entry><literal>t</literal></entry> </row> <row> <entry> <literal>-|-</literal> </entry> - <entry>adjacent?</entry> + <entry>is adjacent to</entry> <entry><literal>numrange(1.1,2.2) -|- numrange(2.2,3.3)</literal></entry> <entry><literal>t</literal></entry> </row> <row> <entry> <literal>+</literal> </entry> - <entry>Union</entry> + <entry>union</entry> <entry><literal>numrange(5,15) + numrange(10,20)</literal></entry> <entry><literal>[5,20)</literal></entry> </row> <row> - <entry> <literal>-</literal> </entry> - <entry>Difference</entry> - <entry><literal>int8range(5,15) - int8range(10,20)</literal></entry> - <entry><literal>[5,10)</literal></entry> - </row> - - <row> <entry> <literal>*</literal> </entry> - <entry>Intersection</entry> + <entry>intersection</entry> <entry><literal>int8range(5,15) * int8range(10,20)</literal></entry> <entry><literal>[10,15)</literal></entry> </row> + <row> + <entry> <literal>-</literal> </entry> + <entry>difference</entry> + <entry><literal>int8range(5,15) - int8range(10,20)</literal></entry> + <entry><literal>[5,10)</literal></entry> + </row> + </tbody> </tgroup> </table> <para> - Range comparisons compare the lower bounds first, and only if - equal, compare the upper bounds. This is generally most useful for - B-tree indexes, rather than being useful comparisons by themselves. + The simple comparison operators <literal><</literal>, + <literal>></literal>, <literal><=</literal>, and + <literal>>=</literal> compare the lower bounds first, and only if those + are equal, compare the upper bounds. These comparisons are not usually + very useful for ranges, but are provided to allow B-tree indexes to be + constructed on ranges. </para> <para> - See <xref linkend="rangetypes"> for more details about range operator - behavior. + The left-of/right-of/adjacent operators always return false when an empty + range is involved; that is, an empty range is not considered to be either + before or after any other range. + </para> + + <para> + The union and difference operators will fail if the resulting range would + need to contain two disjoint sub-ranges, as such a range cannot be + represented. </para> <para> <xref linkend="range-functions-table"> shows the functions - available for use with range types. See <xref linkend="rangetypes"> - for more information and examples of the use of these functions. + available for use with range types. </para> <indexterm> @@ -10658,7 +10671,7 @@ SELECT NULLIF(value, '(none)') ... <function>lower</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> + <entry>range's element type</entry> <entry>lower bound of range</entry> <entry><literal>lower(numrange(1.1,2.2))</literal></entry> <entry><literal>1.1</literal></entry> @@ -10669,7 +10682,7 @@ SELECT NULLIF(value, '(none)') ... <function>upper</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> + <entry>range's element type</entry> <entry>upper bound of range</entry> <entry><literal>upper(numrange(1.1,2.2))</literal></entry> <entry><literal>2.2</literal></entry> @@ -10680,7 +10693,7 @@ SELECT NULLIF(value, '(none)') ... <function>isempty</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> + <entry><type>boolean</type></entry> <entry>is the range empty?</entry> <entry><literal>isempty(numrange(1.1,2.2))</literal></entry> <entry><literal>false</literal></entry> @@ -10691,8 +10704,8 @@ SELECT NULLIF(value, '(none)') ... <function>lower_inc</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> - <entry>is the lower bound of the range inclusive?</entry> + <entry><type>boolean</type></entry> + <entry>is the lower bound inclusive?</entry> <entry><literal>lower_inc(numrange(1.1,2.2))</literal></entry> <entry><literal>true</literal></entry> </row> @@ -10702,8 +10715,8 @@ SELECT NULLIF(value, '(none)') ... <function>upper_inc</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> - <entry>is the upper bound of the range inclusive?</entry> + <entry><type>boolean</type></entry> + <entry>is the upper bound inclusive?</entry> <entry><literal>upper_inc(numrange(1.1,2.2))</literal></entry> <entry><literal>false</literal></entry> </row> @@ -10713,8 +10726,8 @@ SELECT NULLIF(value, '(none)') ... <function>lower_inf</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> - <entry>is the lower bound of the range infinite?</entry> + <entry><type>boolean</type></entry> + <entry>is the lower bound infinite?</entry> <entry><literal>lower_inf('(,)'::daterange)</literal></entry> <entry><literal>true</literal></entry> </row> @@ -10724,8 +10737,8 @@ SELECT NULLIF(value, '(none)') ... <function>upper_inf</function>(<type>anyrange</type>) </literal> </entry> - <entry><type>anyrange</type></entry> - <entry>is the upper bound of the range infinite?</entry> + <entry><type>boolean</type></entry> + <entry>is the upper bound infinite?</entry> <entry><literal>upper_inf('(,)'::daterange)</literal></entry> <entry><literal>true</literal></entry> </row> |