mysqli_stmt::prepare

mysqli_stmt_prepare

(PHP 5, PHP 7, PHP 8)

mysqli_stmt::prepare -- mysqli_stmt_prepare — Prepares an SQL statement for execution

说明

面向对象风格

public mysqli_stmt::prepare(string $query): bool

过程化风格

mysqli_stmt_prepare(mysqli_stmt $statement, string $query): bool

Prepares a statement for execution. The query must consist of a single SQL statement.

The statement template can contain zero or more question mark (?) parameter markers⁠—also called placeholders. The parameter markers must be bound to application variables using mysqli_stmt_bind_param() before executing the statement.

注意:

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.

参数

stmt

仅以过程化样式：由 mysqli_stmt_init() 返回的 statement 标识。

query

The query, as a string. It must consist of a single SQL statement.

The SQL statement may contain zero or more parameter markers represented by question mark (?) characters at the appropriate positions.

注意:

The markers are legal only in certain places in SQL statements. For example, they are permitted 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 permitted for identifiers (such as table or column names), 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.

返回值

成功时返回 true， 或者在失败时返回 false。

范例

示例 #1 mysqli_stmt::prepare() example

面向对象风格

<?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);

过程化风格

<?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);

以上例程会输出：

Amersfoort is in district Utrecht

参见