Question

我有一个包含MySQL变量的查询来生成一个时间值的运行总计，它在PHPMyAdmin中工作并产生结果/行，但是一旦我在我的网站上尝试它就生成"Fatal error: Call to a member function fetch_assoc() on a non-object"。如果有人能帮助我在这里找出问题，我们将不胜感激。

PHPMyAdmin中使用的查询[有效]：

SET @total_duration := 0;
SELECT sec_to_time(@total_duration := @total_duration + time_to_sec(duration)) AS cumulative_duration
FROM tbl_flights
ORDER BY tbl_flights.flight_id ASC

在PHP文件中查询[不起作用]：

<?php

include('config.php');

$sql = "SET @total_duration := 0;
        SELECT sec_to_time(@total_duration := @total_duration + time_to_sec(duration)) AS cumulative_duration
        FROM tbl_flights
        ORDER BY tbl_flights.flight_id ASC";

$result = $conn->query($sql);

while ($row = $result->fetch_assoc()) {

    echo $row['cumulative_duration'];

}

?>

Answer 1

mysqli_query一次只能处理一个查询。您有两种选择：

将它分成两个查询：

$sql = "SELECT sec_to_time(@total_duration := @total_duration + time_to_sec(duration)) AS cumulative_duration
        FROM tbl_flights
        ORDER BY tbl_flights.flight_id ASC";
$conn->query("SET @total_duration := 0");
$result = $conn->query($sql);

或者使用mysqli_multi_query：

$sql = "SET @total_duration := 0;
        SELECT sec_to_time(@total_duration := @total_duration + time_to_sec(duration)) AS cumulative_duration
        FROM tbl_flights
        ORDER BY tbl_flights.flight_id ASC";

$result = $conn->multi_query($sql);

MySQL PHP - 致命错误，查询在页面上失败但不是PHPMyAdmin

1 个答案: