Question

我想获取所有用户数据，但我只获得一个用户详细信息，请帮我解决

$conn = mysqli_connect("localhost", "root", "", "bitmining");
$sql6="SELECT username FROM users";         
if($result = mysqli_query($conn, $sql6)){       
    while ($row=mysqli_fetch_array($result)){               
    //Hashrate Data Fetch
    $investedusername = $row['username'];

    $sql3="SELECT sum(hashrate_amount) as total FROM buyhashrate WHERE invested_username='$investedusername'";
    $result = mysqli_query($conn, $sql3);           
    $row = mysqli_fetch_assoc($result);
    //Total Value of Hashrate
    echo $row['total'] . " GH/s";               
    echo "<br />";      
}
    $result->close();
}

Answer 1

您重新使用$ result字段，将您的第二个引用更改为......

    $result1 = mysqli_query($conn, $sql3);           
    $row = mysqli_fetch_assoc($result1);

这将停止重置

中用于主循环的值

while ($row=mysqli_fetch_array($result)){

Answer 2

对mysqli_query使用$ result变量 $ result = mysqli_query（$ conn，$ sql3）;

Answer 3

虽然其他答案对你的错误是正确的，但我想给你一个更好的解决方案。

尝试使用这样的连接：

$conn = mysqli_connect("localhost", "root", "", "bitmining");
$sql="SELECT SUM(hashrate_amount) AS total FROM users AS t1 LEFT JOIN buyhashrate AS t2 ON (t1.username=t2.invested_username) GROUP BY t1.username";         
if($result = mysqli_query($conn, $sql)){       
    while ($row=mysqli_fetch_array($result)){               
        //Total Value of Hashrate
        echo $row['total'] . " GH/s";               
        echo "<br />";      
    }
    $result->close();
}

这样您只需从数据库中执行一次查询。但是使用你的方法你有n + 1个查询，其中n是用户数。因此，对于一百个用户，有101个查询。

如何从数据库中获取所有用户数据？

3 个答案: