Question

我有一个像

这样的值的SQL列

PT2M52.37S
PT21.79S
PT53M29.68S
P
PT9S

一些 MySQL 函数可以将上述格式转换为秒？

我搜索了所有内容，但没有找到与上述格式完全相同的内容。我试过的任何日期mysql函数都无法正常工作

有关此格式的更多信息：http://www.ostyn.com/standards/scorm/samples/ISOTimeForSCORM.htm

PHP函数（它总是P，第一个字符）

function scorm_format_duration($duration) {
    // Fetch date/time strings.
    $stryears = get_string('years');
    $strmonths = get_string('nummonths');
    $strdays = get_string('days');
    $strhours = get_string('hours');
    $strminutes = get_string('minutes');
    $strseconds = get_string('seconds');

    if ($duration[0] == 'P') {
        // If timestamp starts with 'P' - it's a SCORM 2004 format
        // this regexp discards empty sections, takes Month/Minute ambiguity into consideration,
        // and outputs filled sections, discarding leading zeroes and any format literals
        // also saves the only zero before seconds decimals (if there are any) and discards decimals if they are zero.
        $pattern = array( '#([A-Z])0+Y#', '#([A-Z])0+M#', '#([A-Z])0+D#', '#P(|\d+Y)0*(\d+)M#',
                            '#0*(\d+)Y#', '#0*(\d+)D#', '#P#', '#([A-Z])0+H#', '#([A-Z])[0.]+S#',
                            '#\.0+S#', '#T(|\d+H)0*(\d+)M#', '#0*(\d+)H#', '#0+\.(\d+)S#',
                            '#0*([\d.]+)S#', '#T#' );
        $replace = array( '$1', '$1', '$1', '$1$2 '.$strmonths.' ', '$1 '.$stryears.' ', '$1 '.$strdays.' ',
                            '', '$1', '$1', 'S', '$1$2 '.$strminutes.' ', '$1 '.$strhours.' ',
                            '0.$1 '.$strseconds, '$1 '.$strseconds, '');
    } else {
        // Else we have SCORM 1.2 format there
        // first convert the timestamp to some SCORM 2004-like format for conveniency.
        $duration = preg_replace('#^(\d+):(\d+):([\d.]+)$#', 'T$1H$2M$3S', $duration);
        // Then convert in the same way as SCORM 2004.
        $pattern = array( '#T0+H#', '#([A-Z])0+M#', '#([A-Z])[0.]+S#', '#\.0+S#', '#0*(\d+)H#',
                            '#0*(\d+)M#', '#0+\.(\d+)S#', '#0*([\d.]+)S#', '#T#' );
        $replace = array( 'T', '$1', '$1', 'S', '$1 '.$strhours.' ', '$1 '.$strminutes.' ',
                            '0.$1 '.$strseconds, '$1 '.$strseconds, '' );
    }

    $result = preg_replace($pattern, $replace, $duration);

    return $result;
}

Answer 1

要使STR_TO_DATE有效，您需要为微秒添加%f。

SELECT duration,
CASE
    WHEN duration LIKE 'P%DT%H%M%.%S' THEN STR_TO_DATE(duration, 'P%dDT%HH%iM%s.%fS')
    WHEN duration LIKE 'P%DT%H%M%S' THEN STR_TO_DATE(duration, 'P%dDT%HH%iM%sS')
    WHEN duration LIKE 'PT%H%M%.%S' THEN STR_TO_DATE(duration, 'PT%HH%iM%s.%fS')
    WHEN duration LIKE 'PT%H%M%S' THEN STR_TO_DATE(duration, 'PT%HH%iM%sS')
    WHEN duration LIKE 'PT%M%.%S' THEN STR_TO_DATE(duration, 'PT%iM%s.%fS')
    WHEN duration LIKE 'PT%M%S' THEN STR_TO_DATE(duration, 'PT%iM%sS')
    WHEN duration LIKE 'PT%.%S' THEN STR_TO_DATE(duration, 'PT%s.%fS')
    WHEN duration LIKE 'PT%S' THEN STR_TO_DATE(duration, 'PT%sS')
END as session
FROM db

PT27M59.08S => 00:27:59.080000

PT2H27M37.11S => 02:27:37.110000

P4DT19H46M18.22S => 115:46:18.220000

Answer 2

我已经创建了2个函数，用于将 cmi.session_time 和 cmi.total_time 的结果转换为ISO8601到秒：

CREATE FUNCTION 'ISO8601_duration_delete_miliseconds'('isoDuration' VARCHAR(512)) RETURNS varchar(512) CHARSET latin1
BEGIN
  DECLARE strIndex INT;
  DECLARE strRes varchar(512);

  SET strIndex = INSTR(isoDuration, '.');
  if (strIndex > 0) then
    set strRes = substring(isoDuration, 1, strIndex-1);
    set strRes = concat(strRes, 'S');
  else
    set strRes = isoDuration;
  end if;

  RETURN strRes;
END

最后的功能：

CREATE FUNCTION `iso8601duration_to_seconds`(`isoDuration` VARCHAR(512)) RETURNS int(11)
BEGIN
  DECLARE strIndex INT;
  DECLARE strRes varchar(512);
  DECLARE intRes INT;

  set strRes =  ISO8601_duration_delete_miliseconds(isoDuration);

  if (INSTR(isoDuration, 'H') > 0) then
    set intRes = time_to_sec(str_to_date(strRes, 'PT%HH%iM%sS'));
  elseif (INSTR(isoDuration, 'M') > 0) then
    set intRes = time_to_sec(str_to_date(strRes, 'PT%iM%sS'));
  else
    set intRes = time_to_sec(str_to_date(strRes, 'PT%sS'));
  end if;

  RETURN intRes;
END

Answer 3

我认为这样做没有标准功能。使用str_to_date()是可能的，但是在缺少时间组件时会失败。如果你只有分钟和秒组件，你可以通过字符串操作来做到这一点。

select ((case when p like '%M%S'
              then substring_index(substring_index(p, 'M', 2), 'M', -1)
              when p like '%T%S'
              then substring_index(substring_index(p, 'T', 2), 'T', -1)
              else ''
         end) +
        (case when p like 'T%M'
              then substring_index(substring_index(p, 'T', 2), 'T', -1) + 0
              else 0
         end) * 60
        ) as seconds

随着更多时间组件的添加，这并不容易概括。例如，秒分量是分割器为“M”的第二个元素。或者＆＃39; T＆＃39;。有时候，你只需要想知道ISO委员会在制定这些标准时的想法。

请注意，MySQL使用前导数字（如果有）将字符串转换为数字。以上使用此功能。

如果您支持更复杂的句点格式，那么我建议您编写一个用户定义的函数并将其作为答案发布在此处。

我还要注意SAS支持这种格式。更好的是，他们真的很好documentation解释它。

编辑：

使用此kludge，您可以更轻松地处理所有格式。它在每个组件后插入一个空格，然后使用substring_index()：

select (case when newp like '%S'
             then substring_index(substring_index(newp, 'S', 1), ' ', -1) + 1
             else 0
        end) as seconds,
       (case when newp like '%M%'
             then substring_index(substring_index(newp, 'M', 1), ' ', -1) + 1
             else 0
        end) as minutes,
       . . .
from (select replace(replace(replace(replace(replace(p, 'T', 'T '
                                                    ), 'Y', 'Y '
                                            ), 'D', 'D '
                                    ), 'H', 'H '
                            ), 'S', 'S '
                    ) as newp
      from t
     ) t

使用MySQL

3 个答案: