CAST datetime字段到日期

select  CAST(datetime_field as DATE), count(*) as count from table group by CAST(datetime_field as DATE);

CAST datetime字段到日期

select  CAST(datetime_field as DATE), count(*) as count from table group by CAST(datetime_field as DATE);

GROUP BY DATEADD(day, DATEDIFF(day, 0, MyDateTimeColumn), 0)

或者在SQL Server 2008以后，你可以像@Oded建议的那样简单地转换为Date:

GROUP BY CAST(orderDate AS DATE)

下面是我使用的一个例子，当我需要计算特定日期的记录数量而不包括时间部分时:

select count(convert(CHAR(10), dtcreatedate, 103) ),convert(char(10), dtcreatedate, 103)
FROM dbo.tbltobecounted
GROUP BY CONVERT(CHAR(10),dtcreatedate,103)
ORDER BY CONVERT(CHAR(10),dtcreatedate,103)

GROUP BY DATE(date_time_column)

在Sql 2008之前，通过去掉日期部分:

GROUP BY CONVERT(CHAR(8),DateTimeColumn,10)