(PHP 5, PHP 7)
mysqli_stmt::$param_count -- mysqli_stmt_param_count — Returns the number of parameter for the given statement
面向对象风格
过程化风格
Returns the number of parameter markers present in the prepared statement.
Returns an integer representing the number of parameters.
Example #1 面向对象风格
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($stmt = $mysqli->prepare("SELECT Name FROM Country WHERE Name=? OR Code=?")) {
$marker = $stmt->param_count;
printf("Statement has %d markers.\n", $marker);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 过程化风格
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($stmt = mysqli_prepare($link, "SELECT Name FROM Country WHERE Name=? OR Code=?")) {
$marker = mysqli_stmt_param_count($stmt);
printf("Statement has %d markers.\n", $marker);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
以上例程会输出：
Statement has 2 markers.
This parameter (and presumably any other parameter in mysqli_stmt) will raise an error with the message "Property access is not allowed yet" if the statement was not prepared properly, or not prepared at all.
To prevent this, always ensure that the return value of the "prepare" statement is true before accessing these properties.