Question

我有这个数据表：

+-ID-+-sensorID-+----date---+-value-+
| 1  | 1        |'some date'|  20   |
| 2  | 1        |'some date'|  15   |
| 3  | 1        |'some date'|  18   |
| 4  | 2        |'some date'|  40   |
| 5  | 2        |'some date'|  68   |
| 6  | 2        |'some date'|  55   |

现在我想在php中创建一个这样的数组：

date - value sensorID(1) - value sensorID(2)

每当日期只有一个传感器值时，我还需要显示一些内容：

[date] => 01-01-2014 [value] => 50 [value] => 60
[date] => 02-01-2014 [value] => 20 [value] => 30
[date] => 03-01-2014 [value] => null [value] => 55
[date] => 04-01-2014 [value] => 20 [value] => 33

如何通过一些简单的步骤有效地完成这项工作？否则我只会为ID 1和ID 2创建一个结果，或者在整个数组上运行我的函数两次。

Answer 1

只需在一次运行中获取所有数据并在PHP中构建数组：

// do the mysql query stuff >> $result (array of all rows in db)
$data = array();
foreach ($result AS $row) {
  if (!isset($data[$row['date']])) {
    $data[$row['date']] = array('sensor1' => null, 'sensor2' => null);
  }
  $data[$row['date']]['sensor' . $row['sensorID']] = $row['value'];
}

结果将类似于

$data = array(
  '01-01-2014' => array('sensor1' => 50, 'sensor2' => 60),
  '02-01-2014' => array('sensor1' => 20, 'sensor2' => 30),
  '03-01-2014' => array('sensor1' => null, 'sensor2' => 55),
  '04-01-2014' => array('sensor1' => 20, 'sensor2' => 33)
);

在结果中组合行

1 个答案: