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<refentry xml:id="mysqli-stmt.prepare" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>mysqli_stmt::prepare</refname>
  <refname>mysqli_stmt_prepare</refname>
  <refpurpose>Prepares an SQL statement for execution</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <para>&style.oop;</para>
  <methodsynopsis role="mysqli_stmt">
   <modifier>public</modifier> <type>bool</type><methodname>mysqli_stmt::prepare</methodname>
   <methodparam><type>string</type><parameter>query</parameter></methodparam>
  </methodsynopsis>
  <para>&style.procedural;</para>
  <methodsynopsis>
   <type>bool</type><methodname>mysqli_stmt_prepare</methodname>
   <methodparam><type>mysqli_stmt</type><parameter>statement</parameter></methodparam>
   <methodparam><type>string</type><parameter>query</parameter></methodparam>
  </methodsynopsis>
  <para>
   Prepares a statement for execution.
   The query must consist of a single SQL statement.
  </para>
  <para>
   The statement template can contain zero or more question mark
   (<literal>?</literal>) parameter markers⁠—also called placeholders.
   The parameter markers must be bound to application variables using
   <function>mysqli_stmt_bind_param</function> before executing the statement.
  </para>
  <note>
   <para>
    In the case where a statement is passed to
    <function>mysqli_stmt_prepare</function> that is longer than
    <literal>max_allowed_packet</literal> of the server, the returned
    error codes are different depending on whether you are using MySQL
    Native Driver (<literal>mysqlnd</literal>) or MySQL Client Library
    (<literal>libmysqlclient</literal>). The behavior is as follows:
   </para>
   <itemizedlist>
    <listitem>
     <para>
      <literal>mysqlnd</literal> on Linux returns an error code of 1153.
      The error message means <quote>got a packet bigger than
      <literal>max_allowed_packet</literal> bytes</quote>.
     </para>
    </listitem>
    <listitem>
     <para>
      <literal>mysqlnd</literal> on Windows returns an error code 2006.
      This error message means <quote>server has gone away</quote>.
     </para>
    </listitem>
    <listitem>
     <para>
      <literal>libmysqlclient</literal> on all platforms returns an error code
      2006. This error message means <quote>server has gone
      away</quote>.
     </para>
    </listitem>
   </itemizedlist>
  </note>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    &mysqli.stmt.description;
    <varlistentry>
     <term><parameter>query</parameter></term>
     <listitem>
      <para>
       The query, as a string. It must consist of a single SQL statement.
      </para>
      <para>
       The SQL statement may contain zero or more parameter markers
       represented by question mark (<literal>?</literal>) characters
       at the appropriate positions.
      </para>
      <note>
<!-- Copied from https://dev.mysql.com/doc/c-api/8.0/en/mysql-stmt-prepare.html -->
       <para>
        The markers are legal only in certain places in SQL statements.
        For example, they are permitted in the <literal>VALUES()</literal>
        list of an <literal>INSERT</literal> statement (to specify column
        values for a row), or in a comparison with a column in a
        <literal>WHERE</literal> clause to specify a comparison value.
        However, they are not permitted for identifiers (such as table or
        column names).
       </para>
      </note>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   &return.success;
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  &mysqli.conditionalexception;
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <example>
   <title><methodname>mysqli_stmt::prepare</methodname> example</title>
   <para>&style.oop;</para>
   <programlisting role="php">
<![CDATA[
<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$city = "Amersfoort";

/* create a prepared statement */
$stmt = $mysqli->stmt_init();
$stmt->prepare("SELECT District FROM City WHERE Name=?");

/* bind parameters for markers */
$stmt->bind_param("s", $city);

/* execute query */
$stmt->execute();

/* bind result variables */
$stmt->bind_result($district);

/* fetch value */
$stmt->fetch();

printf("%s is in district %s\n", $city, $district);
]]>
   </programlisting>
   <para>&style.procedural;</para>
   <programlisting role="php">
<![CDATA[
<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

$city = "Amersfoort";

/* create a prepared statement */
$stmt = mysqli_stmt_init($link);
mysqli_stmt_prepare($stmt, "SELECT District FROM City WHERE Name=?");

/* bind parameters for markers */
mysqli_stmt_bind_param($stmt, "s", $city);

/* execute query */
mysqli_stmt_execute($stmt);

/* bind result variables */
mysqli_stmt_bind_result($stmt, $district);

/* fetch value */
mysqli_stmt_fetch($stmt);

printf("%s is in district %s\n", $city, $district);
]]>
   </programlisting>
   &examples.outputs;
   <screen>
<![CDATA[
Amersfoort is in district Utrecht
]]>
   </screen>
  </example>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mysqli_stmt_init</function></member>
    <member><function>mysqli_stmt_execute</function></member>
    <member><function>mysqli_stmt_fetch</function></member>
    <member><function>mysqli_stmt_bind_param</function></member>
    <member><function>mysqli_stmt_bind_result</function></member>
    <member><function>mysqli_stmt_get_result</function></member>
    <member><function>mysqli_stmt_close</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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