php-doc-en/reference/mysql/functions/mysql-query.xml

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<refentry xml:id="function.mysql-query" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>mysql_query</refname>
  <refpurpose>Send a MySQL query</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <warning>
   &mysql.alternative.note;
   <simplelist role="alternatives">
    <member><function>mysqli_query</function></member>
    <member><methodname>PDO::query</methodname></member>
   </simplelist>
  </warning>
 </refsynopsisdiv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>mixed</type><methodname>mysql_query</methodname>
   <methodparam><type>string</type><parameter>query</parameter></methodparam>
   <methodparam choice="opt"><type>resource</type><parameter>link_identifier</parameter><initializer>NULL</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>mysql_query</function> sends a unique query (multiple queries
   are not supported) to the currently
   active database on the server that's associated with the
   specified <parameter>link_identifier</parameter>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>query</parameter></term>
     <listitem>
      <para>
       An SQL query
      </para>
      <para>
       The query string should not end with a semicolon.
       Data inside the query should be <link
       linkend="function.mysql-real-escape-string">properly escaped</link>.
      </para>
     </listitem>
    </varlistentry>
    &mysql.linkid.description;
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset,
   <function>mysql_query</function> 
   returns a <type>resource</type> on success, or &false; on
   error.
  </para>
  <para>
   For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc,
   <function>mysql_query</function> returns &true; on success
   or &false; on error.
  </para>
  <para>
   The returned result resource should be passed to
   <function>mysql_fetch_array</function>, and other
   functions for dealing with result tables, to access the returned data.
  </para>
  <para>
   Use <function>mysql_num_rows</function> to find out how many rows
   were returned for a SELECT statement or
   <function>mysql_affected_rows</function> to find out how many
   rows were affected by a DELETE, INSERT, REPLACE, or UPDATE
   statement.
  </para>
  <para>
   <function>mysql_query</function> will also fail and return &false;
   if the user does not have permission to access the table(s) referenced by
   the query.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>Invalid Query</title>
    <para>
     The following query is syntactically invalid, so
     <function>mysql_query</function> fails and returns &false;.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
$result = mysql_query('SELECT * WHERE 1=1');
if (!$result) {
    die('Invalid query: ' . mysql_error());
}

?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title>Valid Query</title>
    <para>
     The following query is valid, so <function>mysql_query</function>
     returns a <type>resource</type>.
    </para>
    <programlisting role="php">
<![CDATA[
<?php
// This could be supplied by a user, for example
$firstname = 'fred';
$lastname  = 'fox';

// Formulate Query
// This is the best way to perform an SQL query
// For more examples, see mysql_real_escape_string()
$query = sprintf("SELECT firstname, lastname, address, age FROM friends 
    WHERE firstname='%s' AND lastname='%s'",
    mysql_real_escape_string($firstname),
    mysql_real_escape_string($lastname));

// Perform Query
$result = mysql_query($query);

// Check result
// This shows the actual query sent to MySQL, and the error. Useful for debugging.
if (!$result) {
    $message  = 'Invalid query: ' . mysql_error() . "\n";
    $message .= 'Whole query: ' . $query;
    die($message);
}

// Use result
// Attempting to print $result won't allow access to information in the resource
// One of the mysql result functions must be used
// See also mysql_result(), mysql_fetch_array(), mysql_fetch_row(), etc.
while ($row = mysql_fetch_assoc($result)) {
    echo $row['firstname'];
    echo $row['lastname'];
    echo $row['address'];
    echo $row['age'];
}

// Free the resources associated with the result set
// This is done automatically at the end of the script
mysql_free_result($result);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mysql_connect</function></member>
    <member><function>mysql_error</function></member>
    <member><function>mysql_real_escape_string</function></member>
    <member><function>mysql_result</function></member>
    <member><function>mysql_fetch_assoc</function></member>
    <member><function>mysql_unbuffered_query</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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