如何在 SQL 服务器中获取完整的毫秒数？

Question

DECLARE @Now DATETIME2(7) = SYSDATETIME();

SELECT
    [Datetime2(1)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(1))),
    [Datetime2(2)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(2))),
    [Datetime2(3)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(3))),
    [Datetime2(4)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(4))),
    [Datetime2(5)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(5))),
    [Datetime2(6)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(6))),
    [Datetime2(7)] = DATEPART(MILLISECOND,CAST(@Now AS DATETIME2(7)))

执行 returns 以下示例值：

300 260 265 264 264 264 264

如何获得更高的精度？

Answer 1

没关系，函数 returns 是一个 int，这不是我所期望的。我应该使用 NANOSECOND，并将其划分。

DECLARE @Now DATETIME2(7) = SYSDATETIME();

SELECT
    [Datetime2(1)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(1)))/1000000.0,
    [Datetime2(2)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(2)))/1000000.0,
    [Datetime2(3)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(3)))/1000000.0,
    [Datetime2(4)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(4)))/1000000.0,
    [Datetime2(5)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(5)))/1000000.0,
    [Datetime2(6)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(6)))/1000000.0,
    [Datetime2(7)] = DATEPART(NANOSECOND,CAST(@Now AS DATETIME2(7)))/1000000.0

如何在 SQL 服务器中获取完整的毫秒数？

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datetime2

datepart