MySQL and PHP
Copyright 1997-2021 the PHP Documentation Group.
mysqli::prepare
mysqli_prepare
Prepare an SQL statement for execution
Object oriented style
public mysqli_stmt mysqli::prepare(string query);
Procedural style
mysqli_stmt mysqli_prepare(mysqli link,
string query);
Prepares the SQL query, and returns a statement handle to be used for further operations on the statement. The query must consist of a single SQL statement.
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.
link
Procedural style only: A link identifier returned by
mysqli_connect
or
mysqli_init
query
The query, as a string.
You should not add a terminating semicolon or
\g
to the statement.
This parameter can include one or more parameter markers
in the SQL statement by embedding question mark
(?
) characters at the appropriate
positions.
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. It's
not allowed to compare marker with
NULL
by ? IS
NULL
too. In general, parameters are legal
only in Data Manipulation Language (DML) statements,
and not in Data Definition Language (DDL) statements.
mysqli_prepare
returns a statement object or false
if an
error occurred.
Example 3.59 mysqli::prepare
example
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(); } $city = "Amersfoort"; /* create a prepared statement */ if ($stmt = $mysqli->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(); ?>
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(); } $city = "Amersfoort"; /* create a prepared statement */ if ($stmt = mysqli_prepare($link, "SELECT District FROM City WHERE Name=?")) { /* bind parameters for markers */ mysqli_stmt_bind_param($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_execute
|
mysqli_stmt_fetch
|
mysqli_stmt_bind_param
|
mysqli_stmt_bind_result
|
mysqli_stmt_close
|