如何选择 COUNT DISTINCT？

Question

我无法选择 COUNT distinct：我需要的答案是 6。 时间差异小于 300 秒，计为 1。 我的 sql：

SELECT COUNT(DISTINCT(cast([Date] as date) + cast([time] as datetime)))
FROM [Table1]WHERE [DATE] = '2013-06-22'
AND ErrCode = 'Scrubber Failure'AND Frequency = 1

Answer 1

更新

SELECT COUNT(DISTINCT 
             ROUND(CONVERT(DECIMAL(20, 4), 
                     DATEDIFF(minute, 
                              CONVERT(datetime, '2013-01-01 00:00:00', 120), 
                              CONVERT(datetime, date + ' ' + time, 120))) / 5, 0)) n
  FROM table1
 WHERE date = '2013-06-22'
   AND errcode = 'Scrubber Failure'
   AND frequency = 1

输出：

| N | ----- | 6 |

这里是 SQLFiddle 演示。