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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<refentry id="fn_equ">
<refmeta>
<refentrytitle>equ</refentrytitle>
<refmiscinfo>number</refmiscinfo>
</refmeta>
<refnamediv>
<refname>lt</refname>
<refname>lte</refname>
<refname>gt</refname>
<refname>gte</refname>
<refname>equ</refname>
<refname>neq</refname>
<refpurpose>comparison functions</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="fsyn_lt">
<funcprototype id="fproto_lt">
<funcdef><function>lt</function></funcdef>
<paramdef>in <parameter>arg1</parameter>any</paramdef>
<paramdef>in <parameter>arg2</parameter>any</paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_lte">
<funcprototype id="fproto_lte">
<funcdef> <function>lte</function> </funcdef>
<paramdef>in <parameter>arg1</parameter>any</paramdef>
<paramdef>in <parameter>arg2</parameter>any</paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_gt">
<funcprototype id="fproto_gt">
<funcdef> <function>gt</function> </funcdef>
<paramdef>in <parameter>arg1</parameter>any</paramdef>
<paramdef>in <parameter>arg2</parameter>any</paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_gte">
<funcprototype id="fproto_gte">
<funcdef><function>gte</function></funcdef>
<paramdef>in<parameter>arg1</parameter> any</paramdef>
<paramdef>in<parameter>arg2</parameter> any</paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_equ">
<funcprototype id="fproto_equ">
<funcdef><function>equ</function></funcdef>
<paramdef><parameter>arg1</parameter> any</paramdef>
<paramdef><parameter>arg2</parameter> any</paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis id="fsyn_neq">
<funcprototype id="fproto_neq">
<funcdef><function>neq</function></funcdef>
<paramdef>in <parameter>arg1</parameter>any</paramdef>
<paramdef>in <parameter>arg2</parameter>any</paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="desc_equ"><title>Description</title>
<para>These functions return 1 if their first argument is less than (lt),
less than or equivalent (lte), greater than (gt), greater than or
equivalent (gte), equivalent (equ), or not equivalent (neq) to the
second argument, respectively. If the arguments are not of the same type,
then an appropriate type coercion is done for them before
comparison. </para>
<para>These functions correspond to SQL query operators <, <=, >,
>=, = and <> and are needed because the SQL syntax does not
allow these operators to be used on the left side of
<function>FROM</function> keyword in a <function>SELECT</function>
statement.</para>
</refsect1>
<refsect1 id="params_equ"><title>Parameters</title>
<refsect2>
<title><parameter>arg1</parameter>, <parameter>arg2</parameter></title>
<para><type>integer</type>, <type>float</type>, <type>double
precision</type>, <type>varchar</type> or <type>NULL</type>.</para>
</refsect2>
</refsect1>
<refsect1 id="ret_equ"><title>Return Values</title>
<para>An <type>integer</type> value of 1 or 0 is returned.</para>
</refsect1>
<refsect1 id="examples_equ"><title>Examples</title>
<example id="ex_equ"><title>Simple Example</title>
<screen>
lt('pata','pato') -> 1 (Yes, 'pata' is less than 'pato')
gt('barbar','bar') -> 1 (Yes, 'barbar' is greater than 'bar')
equ(17,17) -> 1 (seventeen is seventeen)
equ(17,17.0) -> 1 (regardless of number format)
equ(atof('17.0'),17.0)) -> 1 (as it seems be)
equ(atof('17.1'),17.1)) -> 0 (But not always! Beware!)
gte(1234,NULL) -> 0 (No, 1234 is not "greater"
than or equal to NULL)
lt(1234,NULL) -> 1 (Instead, it is "less" than NULL)
</screen>
</example>
</refsect1>
</refentry>
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