如何在PHP中使用storedprocedure在日期列中传递null？

CREATE PROCEDURE insert_data(IN date_param DATE)
BEGIN
    INSERT INTO your_table(date_column) VALUES (date_param);
END

CREATE PROCEDURE insert_data(IN date_param DATE)
BEGIN
    IF date_param IS NULL THEN
        INSERT INTO your_table(date_column) VALUES (NULL);
    ELSE
        INSERT INTO your_table(date_column) VALUES (date_param);
    END IF;
END

<?php
$pdo = new PDO("mysql:host=localhost;dbname=your_database", "username", "password");

$date = null; // 设置日期参数为null

$stmt = $pdo->prepare("CALL insert_data(?)");
$stmt->bindParam(1, $date, PDO::PARAM_NULL);
$stmt->execute();
?>