如何选择COUNT DISTINCT？

Question

我有问题SELECT COUNT不同：我需要的答案是6 不同的时间是300秒<在数为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

修订

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。