如何从第一个选择查询结果集中多次运行选择查询？

Question

我似乎无法弄清楚如何从查询中获取结果并在另一个查询中使用它们。为了保持它的简单我只想说我有一个表叫saved_players和设置像这样..

Username  playername 
user1   player1 
user1   player2 
user2   player1 
user1   player3 
user3   player1 

这里是我使用的回声只对已登录用户的所有信息的查询。

$query = "SELECT * FROM saved_players WHERE username = '".$_SESSION['login']."'"; 

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

if (mysqli_num_rows($result) > 0) { 
// output data of each row 

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

    echo " 
    <table class='tablebox' width='300' border='0' cellspacing='0'> 
    <tr> 


    <td width='200' style='color: #4f4e4e; font-size: 19px;'>". $row["[playername"]."</td> 

    </tr> 

    </table>"; 


    } 
} 

?> 

如果用户“用户1”中记录此过程中会显示

player1 
player2 
player3 

如何运行与这些名字的一个新的查询？所有这一切的最终目标是把每个球员的名字从结果（在这种情况下PLAYER1，玩家2，玩家3）和运行与此类似

$query= "SELECT COUNT(playername) AS Totalnumber FROM saved_players WHERE playername = '' "; 

查询我想指望有多少次这些玩家中的每一个都已被所有用户添加到表格saved_players，并将该数字除以我拥有的成员数量。但我只需要登录用户已添加到saved_players的玩家完成此操作。当然，希望这可以帮助任何意义将不胜感激！

Answer 1

使用这个查询： -

$query = "SELECT *,(SELECT COUNT(playername) FROM saved_players as tab1 
WHERE tab1.playername = tab1.playername) 
AS Totalnumber FROM saved_players as tab2 
WHERE username = '".$_SESSION['login']."'" 

MySQL查询这样的： -

SELECT *,(SELECT COUNT(playername) FROM saved_players as tab1 
    WHERE tab1.playername = tab1.playername) 
    AS Totalnumber FROM saved_players as tab2 
    WHERE username = 'user1' 

Answer 2

试试这个代码逻辑：

  <?php 
      $query = "SELECT * FROM saved_players WHERE username = '".$_SESSION['login']."'"; 

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

      if (mysqli_num_rows($result) > 0) { 
      // output data of each row 

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

       echo " 
       <table class='tablebox' width='300' border='0' cellspacing='0'> 
       <tr> 


       <td width='200' style='color: #4f4e4e; font-size: 19px;'>". $row["[playername"]."</td>"; 
      /* 
      Your logic can be placed here... 

$query= "SELECT COUNT(playername) AS Totalnumber FROM saved_players WHERE playername = '' GROUP BY playername HAVING Totalnumber > 0"; 

    The above is only an example... 
    but if you still wish to get 0 number of players then disregard the HAVING Part 
    -------------------------------------------------------------------- 

     // In your inner SQL query you may use group by with HAVING 
      get the value you expect in this query 

      */ 



       echo"</tr> 

       </table>"; 


       } 
      } 

      ?> 

希望这有助于