在两个日期之间进行选择，并从PHP和MySQL中的两个表中选择

$date1 = "2022-01-01";
$date2 = "2022-12-31";

$query = "SELECT * FROM tableA WHERE date_column BETWEEN '$date1' AND '$date2'
          UNION
          SELECT * FROM tableB WHERE date_column BETWEEN '$date1' AND '$date2'";

// 使用mysqli扩展的示例代码
$connection = mysqli_connect("localhost", "username", "password", "database");

if (!$connection) {
    die("数据库连接失败：" . mysqli_connect_error());
}

$result = mysqli_query($connection, $query);

if (!$result) {
    die("查询失败：" . mysqli_error($connection));
}

// 处理查询结果
while ($row = mysqli_fetch_assoc($result)) {
    // 对查询结果进行处理
    // $row包含了每一行的数据，可以根据需要进行处理
    echo $row['column_name'];
}

// 关闭数据库连接
mysqli_close($connection);