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Add string functions: concat(), concat_ws(), left(), right(), and reverse().

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Pavel Stehule, reviewed by me.
This commit is contained in:
Itagaki Takahiro
2010-08-24 06:30:44 +00:00
parent b9defe0405
commit 49b27ab551
7 changed files with 331 additions and 6 deletions
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85
doc/src/sgml/func.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.529 2010/08/17 04:37:20 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.530 2010/08/24 06:30:43 itagaki Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -1250,6 +1250,12 @@
<indexterm>
<primary>chr</primary>
</indexterm>
<indexterm>
<primary>concat</primary>
</indexterm>
<indexterm>
<primary>concat_ws</primary>
</indexterm>
<indexterm>
<primary>convert</primary>
</indexterm>
@ -1268,6 +1274,9 @@
<indexterm>
<primary>initcap</primary>
</indexterm>
<indexterm>
<primary>left</primary>
</indexterm>
<indexterm>
<primary>lpad</primary>
</indexterm>
@ -1295,6 +1304,12 @@
<indexterm>
<primary>replace</primary>
</indexterm>
<indexterm>
<primary>reverse</primary>
</indexterm>
<indexterm>
<primary>right</primary>
</indexterm>
<indexterm>
<primary>rpad</primary>
</indexterm>
@ -1374,6 +1389,34 @@
<entry><literal>A</literal></entry>
</row>
<row>
<entry>
<literal><function>concat</function>(<parameter>str</parameter> <type>"any"</type>
[, <parameter>str</parameter> <type>"any"</type> [, ...] ])</literal>
</entry>
<entry><type>text</type></entry>
<entry>
Concatenate all arguments. NULL arguments are ignored.
</entry>
<entry><literal>concat('abcde', 2, NULL, 22)</literal></entry>
<entry><literal>abcde222</literal></entry>
</row>
<row>
<entry>
<literal><function>concat_ws</function>(<parameter>sep</parameter> <type>text</type>,
<parameter>str</parameter> <type>"any"</type>
[, <parameter>str</parameter> <type>"any"</type> [, ...] ])</literal>
</entry>
<entry><type>text</type></entry>
<entry>
Concatenate all but first arguments with separators. The first
parameter is used as a separator. NULL arguments are ignored.
</entry>
<entry><literal>concat_ws(',', 'abcde', 2, NULL, 22)</literal></entry>
<entry><literal>abcde,2,22</literal></entry>
</row>
<row>
<entry>
<literal><function>convert</function>(<parameter>string</parameter> <type>bytea</type>,
@ -1465,6 +1508,20 @@
<entry><literal>Hi Thomas</literal></entry>
</row>
<row>
<entry>
<literal><function>left</function>(<parameter>str</parameter> <type>text</type>,
<parameter>n</parameter> <type>int</type>)</literal>
</entry>
<entry><type>text</type></entry>
<entry>
Return first <replaceable>n</> characters in the string. When <replaceable>n</>
is negative, return all but last |<replaceable>n</>| characters.
</entry>
<entry><literal>left('abcde', 2)</literal></entry>
<entry><literal>ab</literal></entry>
</row>
<row>
<entry><literal><function>length</function>(<parameter>string</parameter>)</literal></entry>
<entry><type>int</type></entry>
@ -1678,6 +1735,32 @@
<entry><literal>abXXefabXXef</literal></entry>
</row>
<row>
<entry>
<literal><function>reverse</function>(<parameter>str</parameter>)</literal>
</entry>
<entry><type>text</type></entry>
<entry>
Return reversed string.
</entry>
<entry><literal>reverse('abcde')</literal></entry>
<entry><literal>edcba</literal></entry>
</row>
<row>
<entry>
<literal><function>right</function>(<parameter>str</parameter> <type>text</type>,
<parameter>n</parameter> <type>int</type>)</literal>
</entry>
<entry><type>text</type></entry>
<entry>
Return last <replaceable>n</> characters in the string. When <replaceable>n</>
is negative, return all but first |<replaceable>n</>| characters.
</entry>
<entry><literal>right('abcde', 2)</literal></entry>
<entry><literal>de</literal></entry>
</row>
<row>
<entry>
<literal><function>rpad</function>(<parameter>string</parameter> <type>text</type>,