Question

我正在尝试向mysql查询平均SUM时间（取自datetime字段）的多条记录，以获得如下输出： 22:38

我的日期时间字段checkin_time包含如下数据：

2012-03-16 22:48:00 // the time here: 22:48 is what's interesting to me
2012-03-16 02:28:32
2012-03-16 00:28:47
0000-00-00 00:00:00

我的计划是从所有日期时间字段中提取并选择总和时间，然后将总和转换为unix时间戳，将总和除以记录总数，最后将其转换回时间格式。然而，这（见下面的代码）没有给我什么，没有错误没有任何东西。我也意识到空字段如：0000-00-00 00:00:00 不考虑来生成相关数据。

任何人都可以帮助我指出错误或者解释你如何做的理论背后的理论？这是我到目前为止所得到的：

修改：感谢 Damiqib 提出有效的SQL查询，但仍然不完全正确。当应该是23:15 时，下面的代码输出 01:00 。

 $getCheckinTime = mysql_query("SELECT COUNT(id), SEC_TO_TIME( AVG( TIME_TO_SEC(  `checkin_time` ) ) ) AS averageTime FROM guests WHERE checkin_time != '0000-00-00 00:00:00'") or die(mysql_error());
while($checkIn = mysql_fetch_array($getCheckinTime)) { 

    $timestamp = strtotime($checkIn['averageTime']);
    $UnixTimeStamp = date("Y-m-d H:i:s", $timestamp); //converting to unix
    $avgUnix = $UnixTimeStamp / $checkIn['COUNT(id)']; // calculating average
    $avgTime = date('H:i', $avgUnix); // convert back to time his format
    echo $avgTime; //outputs 01:00, got to be incorrect should be 23:15 something

}

提前致谢

编辑：解决方案（感谢Damiqib）：

$avgCheckinTime = array();
$getCheckinTime = mysql_query("SELECT TIME(`checkin_time`) AS averageTime    FROM guests    WHERE checkin_time !=  '0000-00-00 00:00:00'") or die(mysql_error());
while($checkIn = mysql_fetch_array($getCheckinTime)) { 

    array_push($avgCheckinTime, $checkIn['averageTime']);
}

// = array('22:00:00', '22:30:00'...)
    $times = $avgCheckinTime;

    $fromReplace = array('22' => '00',
                   '23' => '01',
                   '00' => '02',
                   '01' => '03',
                   '02' => '04',
                   '03' => '05',
                   '04' => '06',
                   '05' => '07');

  $timeSum = 0;

  //Iterate through all given times and convert them to seconds
  foreach ($times as $time) {
   if (preg_match ('#^(?<hours>[\d]{2}):(?<mins>[\d]{2}):(?<secs>[\d]{2})$#',$time, $parse)) {
  $timeSum += (int) $fromReplace[$parse['hours']] * 3600 + (int) $parse['mins'] * 60 + (int) $parse['secs'] . '<br />';

  //echo $time . ' ' . ($fromReplace[$parse['hours']] *3600) .  '<br />'; 
  }
}

   $toReplace = array('00' => '22',
                 '01' => '23',
                 '02' => '00',
                 '03' => '01',
                 '04' => '02',
                 '05' => '03',
                 '06' => '04',
                 '07' => '05');

 $time = explode(':', gmdate("H:i:s", $timeSum / count($times)));

 $averageCheckinTime = $toReplace[$time[0]] . ':' . $time[1] . ':' . $time[2];

 //This is the final average time biased between 22-05
 echo $averageCheckinTime;

Answer 1

这似乎适用于我的测试数据：

SELECT SEC_TO_TIME(AVG(TIME_TO_SEC(`time`))) AS averageTime
FROM guests 
WHERE checkin_time != '0000-00-00 00:00:00'

<强>更新

-- Table structure for table `guests`
CREATE TABLE `guests` (
  `checkin_time` datetime NOT NULL,
  KEY `checkin_time` (`checkin_time`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

-- Dumping data for table `guests`
INSERT INTO `guests` VALUES('2012-08-17 17:30:00');
INSERT INTO `guests` VALUES('2012-08-17 18:30:00');
INSERT INTO `guests` VALUES('2012-08-17 19:30:00');
INSERT INTO `guests` VALUES('2012-08-17 20:30:00');
INSERT INTO `guests` VALUES('2012-08-17 21:30:00');


Showing rows 0 - 0 (1 total, Query took 0.0003 sec)
SELECT SEC_TO_TIME( AVG( TIME_TO_SEC(  `checkin_time` ) ) ) AS averageTime
FROM guests
WHERE checkin_time !=  '0000-00-00 00:00:00'
LIMIT 0 , 30

<强>结果

averageTime
19:30:00

至少我的测试数据似乎有效吗？

另一个更新

<?php

  /*
    SELECT TIME(`checkin_time`) AS averageTime
    FROM guests
    WHERE checkin_time !=  '0000-00-00 00:00:00'
  */

  // = array('22:00:00', '22:30:00'...)
  $times = RESULT_FROM_QUERY_AS_AN_ARRAY_OF_TIMES;

  $fromReplace = array('22' => '00',
                       '23' => '01',
                       '00' => '02',
                       '01' => '03',
                       '02' => '04',
                       '03' => '05',
                       '04' => '06',
                       '05' => '07');

  $timeSum = 0;

  //Iterate through all given times and convert them to seconds
  foreach ($times as $time) {
    if (preg_match ('#^(?<hours>[\d]{2}):(?<mins>[\d]{2}):(?<secs>[\d]{2})$#',$time, $parse)) {
      $timeSum += (int) $fromReplace[$parse['hours']] * 3600 + (int) $parse['mins'] * 60 + (int) $parse['secs'] . '<br />';

      echo $time . ' ' . ($fromReplace[$parse['hours']] *3600) .  '<br />'; 
    }
  }

  $toReplace = array('00' => '22',
                     '01' => '23',
                     '02' => '00',
                     '03' => '01',
                     '04' => '02',
                     '05' => '03',
                     '06' => '04',
                     '07' => '05');

  $time = explode(':', gmdate("H:i:s", $timeSum / count($times)));

  $averageCheckinTime = $toReplace[$time[0]] . ':' . $time[1] . ':' . $time[2];

  //This is the final average time biased between 22-05
  echo $averageCheckinTime;   

?>

PHP SQL：从多个日期时间记录中选择SUM时间的AVG？

1 个答案: