MySQL and PHP
Copyright 1997-2021 the PHP Documentation Group.
mysqli_stmt::prepare
mysqli_stmt_prepare
Prepare an SQL statement for execution
Object oriented style
public mixed mysqli_stmt::prepare(string query);
Procedural style
bool mysqli_stmt_prepare(mysqli_stmt stmt,
string query);
Prepares the SQL query pointed to by the null-terminated string query.
The parameter markers must be bound to application variables
using
mysqli_stmt_bind_param
and/or
mysqli_stmt_bind_result
before executing the statement or fetching rows.
In the case where you pass a statement to
mysqli_stmt_prepare
that is longer than max_allowed_packet
of
the server, the returned error codes are different depending
on whether you are using MySQL Native Driver
(mysqlnd
) or MySQL Client Library
(libmysqlclient
). The behavior is as
follows:
mysqlnd
on Linux returns an error code
of 1153. The error message means “got a packet
bigger than max_allowed_packet
bytes”.
mysqlnd
on Windows returns an error
code 2006. This error message means “server has gone
away”.
libmysqlclient
on all platforms returns
an error code 2006. This error message means “server
has gone away”.
stmt
Procedural style only: A statement identifier returned
by
mysqli_stmt_init
.
query
The query, as a string. It must consist of a single SQL statement.
You can include one or more parameter markers in the SQL
statement by embedding question mark
(?
) characters at the appropriate
positions.
You should not add a terminating semicolon or
\g
to the statement.
The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.
However, they are not allowed for identifiers (such as
table or column names), in the select list that names
the columns to be returned by a SELECT statement), or
to specify both operands of a binary operator such as
the =
equal sign. The latter
restriction is necessary because it would be
impossible to determine the parameter type. In
general, parameters are legal only in Data
Manipulation Language (DML) statements, and not in
Data Definition Language (DDL) statements.
Returns true
on success or
false
on failure.
Example 3.96 Object oriented style
<?php $mysqli = new mysqli("localhost", "my_user", "my_password", "world"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } $city = "Amersfoort"; /* create a prepared statement */ $stmt = $mysqli->stmt_init(); if ($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); /* close statement */ $stmt->close(); } /* close connection */ $mysqli->close(); ?>
Example 3.97 Procedural style
<?php $link = mysqli_connect("localhost", "my_user", "my_password", "world"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } $city = "Amersfoort"; /* create a prepared statement */ $stmt = mysqli_stmt_init($link); if (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, $district); /* close statement */ mysqli_stmt_close($stmt); } /* close connection */ mysqli_close($link); ?>
The above examples will output:
Amersfoort is in district Utrecht
mysqli_stmt_init
|
mysqli_stmt_execute
|
mysqli_stmt_fetch
|
mysqli_stmt_bind_param
|
mysqli_stmt_bind_result
|
mysqli_stmt_get_result
|
mysqli_stmt_close
|