从SQL查询中获取一行数

Question

我试图弄清楚如何从SQL表中获取一行数。在我的情况下，我需要根据他/她的分数得到用户的排名。我有下面的代码将做到这一点，但是有没有更好的方法来帮助这只是一个查询？

$rank = 0; 
$username = $_SESSION['user']; 

    $query = "SELECT username, SUM(`score`) as total_score FROM answers GROUP BY username ORDER BY total_score DESC"; 
     if ($stmt = mysqli_prepare($connect, $query)) { 
       mysqli_stmt_bind_param($stmt); 
       mysqli_stmt_execute($stmt); 
       mysqli_stmt_bind_result($stmt, $uname, $score); 
         while (mysqli_stmt_fetch($stmt)) { 
          $user = $uname; 
          $rank++; 
            if ($user == $username) { 
             echo $rank; 
             break; 
             } 
           } 
           mysqli_stmt_close($stmt); 
         } 

Answer 1

你可以从你的SQL取得名次

SELECT username, SUM(`score`) as total_score,@curRank := @curRank + 1 AS rank FROM answers,(SELECT @curRank := 0) GROUP BY username ORDER BY total_score DESC 


example 

select DONATUR,COUNT(DISTINCT AREA) ,@curRank := @curRank + 1 AS rank from funding,(SELECT @curRank := 0) r group by Donatur; 
+---------+----------------------+------+ 
| DONATUR | COUNT(DISTINCT AREA) | rank | 
+---------+----------------------+------+ 
| Mr.X |     3 | 1 | 
| Mr.Y |     1 | 2 | 
| Mr.Z |     2 | 3 | 
+---------+----------------------+------+ 
3 rows in set (0.00 sec) 

，如果你想在列表中只有一个用户，你可以像这样

mysql> select DONATUR,COUNT(DISTINCT AREA) ,@curRank := @curRank + 1 AS rank from funding,(SELECT @curRank := 0) r group by Donatur having DONATUR="Mr.Y"; 
+---------+----------------------+------+ 
| DONATUR | COUNT(DISTINCT AREA) | rank | 
+---------+----------------------+------+ 
| Mr.Y |     1 | 2 | 
+---------+----------------------+------+ 
1 row in set (0.00 sec) 

使用此查询

SELECT @curRank := @curRank + 1 AS rank,username,score from (select username,COUNT(DISTINCT score) AS score from answers group by username order by COUNT(DISTINCT score)) y,(SELECT @curRank := 0) r where username=?";