Question

我将此作为我的函数来整理多个值（在我的情况下是平均值），我已经可以输出最高的值（平均值）。我现在要做的不是输出最高值（平均值）而是输出包含最高值（平均值）的列名。我尝试了mysql_fetch_field()，但它为我输出了null。另外，有没有办法计算average($averagesa)？

<?php

    usort($averagesa, function($a, $b) {  // $averagesa contains several averages
    if ($a['avg'] == $b['avg']) {         // from multiple queries
           return 0;
    }

    return ($a['avg'] > $b['avg']) ? -1 : 1;
    });

    $highesta = $averagesa[0];   
    echo $highesta['avg'];               // highest average value

?>

这是示例查询，我想输出列（即C1.1），如果它包含最高的平均值

  <html>
<table>
<tr><th>Campus</th>
<th>No. of Staff</th>
<th>C1.1</th>
<th>C1.2</th>
<th>C1.3</th>
<th>C1.4</th>
<th>C1.5</th>
<th>C1.6</th>
<th>C2.1</th>
<th>C2.2</th>
<th>C2.3</th>
<th>C3.1</th>
<th>C3.2</th>
<th>C3.3</th>
<th>C3.4</th>
<th>AVERAGE</th>
</tr>
<tbody>
<tr>
    <td>MAIN 1 - CABEIHM</td>
<?php

    $querya1 = ("SELECT ROUND(AVG(Compv11),2), dept_code, camp_code
                 FROM performance 
                 INNER JOIN employment 
                 ON employment.emp_code=performance.emp_id 
                 AND employment.dept_code=performance.dept_id
                 WHERE empg_code=1  AND dept_id=3");

    $resulta1 = mysql_query($querya1) or die(mysql_error());

    // Print out result
    while($rowa1 = mysql_fetch_array($resulta1))
    {
        $averagesa[1] = array(
            'avg' => $rowa1['ROUND(AVG(Compv11),2)'],
            'empg_code' => 1,
            'dept_id' => 3,
            'dept_code' => $rowa1['dept_code'],
            'camp_code' => $rowa1['camp_code']
        );
        echo "".$rowa1['ROUND(AVG(Compv11),2)'];
    }

?>

Answer 1

考虑一个纯SQL解决方案，它输出对应于最高平均值的 dept_code 和 camp_code 。将此单行值分配给PHP数组。此外，查询中添加了GROUP BY子句，以确保符合ANSI标准的聚合。

SELECT t.dept_code, t.camp_code, t.avg_comp
FROM
  (SELECT ROUND(AVG(Compv11),2) as avg_comp, dept_code, camp_code
   FROM performance 
   INNER JOIN employment 
   ON employment.emp_code=performance.emp_id 
   AND employment.dept_code=performance.dept_id
   WHERE empg_code=1  AND dept_id=3
   GROUP BY dept_code, camp_code) as t
ORDER BY t.avg_comp DESC
LIMIT 1

从数组中输出列名并计算数组的平均值

1 个答案: