在 SQL Server 中刪除日期時間的時間部分的最佳方法 - Best approach to remove time part of datetime in SQL Server

問題：

Which method provides the best performance when removing the time portion from a datetime field in SQL Server?從 SQL Server 中的日期時間字段中刪除時間部分時，哪種方法可提供最佳性能？

a) select DATEADD(dd, DATEDIFF(dd, 0, getdate()), 0)

or要麼

b) select cast(convert(char(11), getdate(), 113) as datetime)

The second method does send a few more bytes either way but that might not be as important as the speed of the conversion.第二種方法確實會多發送幾個字節，但這可能不如轉換速度重要。

Both also appear to be very fast, but there might be a difference in speed when dealing with hundreds-of-thousands or more rows?兩者看起來也都非常快，但是在處理數十萬或更多行時速度可能會有所不同？

Also, is it possible that there are even better methods to get rid of the time portion of a datetime in SQL?另外，是否有更好的方法可以擺脫 SQL 中日期時間的時間部分？

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解決方案：

參考一： https://en.stackoom.com/question/4wJ7
參考二： https://stackoom.com/question/4wJ7