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$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.249 2005/05/23 01:29:54 neilc Exp $

PostgreSQL documentation

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<entry>

Remove the longest string containing only the

<parameter>characters</parameter> (a space by default) from the

start/end/both ends of the <parameter>string</parameter>.

start/end/both ends of the <parameter>string</parameter>

</entry>

<entry><literal>trim(both 'x' from 'xTomxx')</literal></entry>

<entry><literal>Tom</literal></entry>

<entry>

Remove the longest string consisting only of characters

in <parameter>characters</parameter> (a space by default)

from the start and end of <parameter>string</parameter>.

from the start and end of <parameter>string</parameter>

</entry>

<entry><literal>btrim('xyxtrimyyx', 'xy')</literal></entry>

<entry><literal>trim</literal></entry>

<entry><literal><function>length</function>(<parameter>string</parameter> <type>text</type>)</literal></entry>

<entry><type>integer</type></entry>

<entry>

Number of characters in <parameter>string</parameter>.

Number of characters in <parameter>string</parameter>

<indexterm>

<primary>character string</primary>

<secondary>length</secondary>

<entry>

Remove the longest string containing only characters from

<parameter>characters</parameter> (a space by default) from the start of

<parameter>string</parameter>.

<parameter>string</parameter>

</entry>

<entry><literal>ltrim('zzzytrim', 'xyz')</literal></entry>

<entry><literal>trim</literal></entry>

<entry><type>text</type></entry>

<entry>

Calculates the MD5 hash of <parameter>string</parameter>,

returning the result in hexadecimal.

returning the result in hexadecimal

</entry>

<entry><literal>md5('abc')</literal></entry>

<entry><literal>900150983cd24fb0 d6963f7d28e17f72</literal></entry>

<parameter>to</parameter> <type>text</type>)</literal></entry>

<entry><type>text</type></entry>

<entry>Replace all occurrences in <parameter>string</parameter> of substring

<parameter>from</parameter> with substring <parameter>to</parameter>.

<parameter>from</parameter> with substring <parameter>to</parameter>

</entry>

<entry><literal>replace( 'abcdefabcdef', 'cd', 'XX')</literal></entry>

<entry><literal>abXXefabXXef</literal></entry>

<entry>

Remove the longest string containing only characters from

<parameter>characters</parameter> (a space by default) from the end of

<parameter>string</parameter>.

<parameter>string</parameter>

</entry>

<entry><literal>rtrim('trimxxxx', 'x')</literal></entry>

<entry><literal>trim</literal></entry>

Any character in <parameter>string</parameter> that matches a

character in the <parameter>from</parameter> set is replaced by

the corresponding character in the <parameter>to</parameter>

set.

set

</entry>

<entry><literal>translate('12345', '14', 'ax')</literal></entry>

<entry><literal>a23x5</literal></entry>

<entry><function>get_byte</function>(<parameter>string</parameter>, <parameter>offset</parameter>)</entry>

<entry><type>integer</type></entry>

<entry>

Extract byte from string.

Extract byte from string

<indexterm>

<primary>get_byte</primary>

</indexterm>

<parameter>offset</parameter>, <parameter>newvalue</>)</entry>

<entry><type>bytea</type></entry>

<entry>

Set byte in string.

Set byte in string

<indexterm>

<primary>set_byte</primary>

</indexterm>

<entry><function>get_bit</function>(<parameter>string</parameter>, <parameter>offset</parameter>)</entry>

<entry><type>integer</type></entry>

<entry>

Extract bit from string.

Extract bit from string

<indexterm>

<primary>get_bit</primary>

</indexterm>

<parameter>offset</parameter>, <parameter>newvalue</>)</entry>

<entry><type>bytea</type></entry>

<entry>

Set bit in string.

Set bit in string

<indexterm>

<primary>set_bit</primary>

</indexterm>

<entry>

Remove the longest string consisting only of bytes

in <parameter>bytes</parameter> from the start and end of

<parameter>string</parameter>.

<parameter>string</parameter>

</entry>

<entry><literal>btrim('\\000trim\\000'::bytea, '\\000'::bytea)</literal></entry>

<entry><literal>trim</literal></entry>

<entry><type>text</type></entry>

<entry>

Calculates the MD5 hash of <parameter>string</parameter>,

returning the result in hexadecimal.

returning the result in hexadecimal

</entry>

<entry><literal>md5('Th\\000omas'::bytea)</literal></entry>

<entry><literal>8ab2d3c9689aaf18 b4958c334c82d8b1</literal></entry>

</entry>

<entry><literal>encode('123\\000456'::bytea, 'escape')</literal></entry>

<entry><literal>123\000456</literal></entry>

</row>

</row>

</tbody>

</tgroup>

If a sequence object has been created with default parameters,

<function>nextval</function> calls on it will return successive values

beginning with 1. Other behaviors can be obtained by using

special parameters in the <xref linkend="SQL-CREATESEQUENCE"> command;

special parameters in the <xref linkend="sql-createsequence" endterm="sql-createsequence-title"> command;

see its command reference page for more information.

</para>

<entry><type>setof int</type> or <type>setof bigint</type> (same as argument type)</entry>

<entry>

Generate a series of values, from <parameter>start</parameter> to <parameter>stop</parameter>

with a step size of one.

with a step size of one

</entry>

</row>

<entry><type>setof int</type> or <type>setof bigint</type> (same as argument type)</entry>

<entry>

Generate a series of values, from <parameter>start</parameter> to <parameter>stop</parameter>

with a step size of <parameter>step</parameter>.

with a step size of <parameter>step</parameter>

</entry>

</row>