在php

Question

我正在尝试从PHP中使用MYSQL加入2个表。但是当我得到结果时，它显示出多重结果。我不知道我的剧本中有什么问题。请帮忙。我的脚本如下表所示：

   Table1: purchase
   id      model       quantity     retquantity   
   1        D54          10            NULL
   2        D54         NULL            5
   3        M90          10            NULL
   4        M95          10            NULL
   5        M90           5

  Table2: sale

  id      model       quantity      retquantity
   1        D54          5            NULL
   2        D54         NULL            5
   3        M90         NULL            5
   4        M95           6            NULL
   5        M90          10            Null

我的php脚本：

    <?php
        $count=0;
        $sql = "SELECT purchase.model,sale.model, 
    SUM(purchase.quantity) AS pquantity,SUM(sale.quantity) AS squantity,
    SUM(purchase.retquantity) AS retpquantity,
     SUM(sale.retquantity) AS sretquantity
    FROM (select model,
    sum(quantity) AS pquantity,sum(retquantity) AS retpquantity from 
     purchase group by model)purchase
    INNER JOIN (select model,
     sum(quantity) AS squantity,
    sum(retquantity) AS retsquantity
     from sale group by model)sale
     ON purchase.model=sale.model
    GROUP BY purchase.model,sale.model";

    $result = $cn->query($sql);
    if ($result->num_rows > 0) {

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

    ?>
    <td><?php echo ++$count; ?></td>
                    <td><?php echo $row['model']; ?></td>
                    <td><?php echo $row['pquantity']; ?></td>
                    <td><?php echo $row['squantity']; ?></td>
                    <td><?php echo $row['retpquantity']; ?></td>
                    <td><?php echo $row['retsquantity']; ?></td>

                    <?php }} $cn->close();?>

我没有得到任何结果。请帮忙。

Answer 1

尝试使用此查询可能会有所帮助

SELECT id, SUM(model) as model, SUM(quantity) as quantity, SUM(retquantity) as retquantity FROM (
       SELECT * FROM purchase
       UNION ALL
       SELECT * FROM sale
       UNION ALL
       ) AS somealias GROUP BY id