Question

我有一个显示值的表格：

第1栏：日期
2,3,4列：杂志的名称。

日期列显示今天的日期，列2,3,4显示每个杂志的订阅数量。每天数字都会更改，mysql查询会从数据库中提取数字并将其显示在表格中。

我想显示一行显示连续两天之间的差异，即上/下时对特定杂志的订阅量：Todays value - yesterdays value。

我正在运行的查询位于foreach循环中。我如何计算连续值？

我的代码是：

    foreach($values as $v_date){
$date = $v_date->DATE; 

  $count = $wpdb->get_results($wpdb->prepare(
    " SELECT DISTINCT `date`,
    (select subscriber_count FROM wp_email_signup where LIST_NAME = 'B1' AND date = '$date') as 'B1',
    (select subscriber_count FROM wp_email_signup where LIST_NAME = '2D' AND date = '$date' ) as '2D',
    (select subscriber_count FROM wp_email_signup where LIST_NAME = 'F90' AND date = '$date' ) as 'F90'
        FROM wp_email_signup WHERE date = '$date' "));
echo '<tr>';
        echo '<td>' . $date . '</td>';
foreach($count as $counts){
  $val1 =  $counts->B1;
  $val2 = $counts->2D;
  $val3 = $counts->F90; 
        echo '<td>' . $val1 . '</td>'; 
        echo '<td>' . $val2 . '</td>';
        echo '<td>' . $val3 . '</td>';  


        echo '</tr>';
        echo '<tr class="row_diff">';
        echo '<td></td>';
        echo '<td>' . DIFFERENCE BETWEEN 2 CONSECUTIVE VALUES . '</td>';
        echo '<td>' . DIFFERENCE BETWEEN 2 CONSECUTIVE VALUES . '</td>';
        echo '<td>' . DIFFERENCE BETWEEN 2 CONSECUTIVE VALUES. '</td>';
        echo '</tr>';
    }

}

Answer 1

这样的事情可行。

// set some values to zero so that our subtraction does not produce errors
$prev1 = 0;
$prev2 = 0;
$prev3 = 0;

foreach($count as $counts)
{
    $val1 =  $counts->B1;
    $val2 = $counts->2D;
    $val3 = $counts->F90;

    echo '<td>' . $val1 . '</td>'; 
    echo '<td>' . $val2 . '</td>';
    echo '<td>' . $val3 . '</td>';  

    echo '</tr>';
    echo '<tr class="row_diff">';
    echo '<td></td>';
    echo '<td>' . ($val1 - $prev1) . '</td>';
    echo '<td>' . ($val2 - $prev2) . '</td>';
    echo '<td>' . ($val3 - $prev3) . '</td>';
    echo '</tr>';

    // Set the current loop of values to be subtracted for the next loop
    $prev1 = $val1;
    $prev2 = $val2;
    $prev3 = $val3;
}

计算foreach循环中2个值之间的差异

1 个答案: