尝试：

CREATE FUNCTION dbo.fn_ConvertToDateTime (@Datetime BIGINT)
RETURNS DATETIME
AS
BEGIN
    DECLARE @LocalTimeOffset BIGINT
           ,@AdjustedLocalDatetime BIGINT;
    SET @LocalTimeOffset = DATEDIFF(second,GETDATE(),GETUTCDATE())
    SET @AdjustedLocalDatetime = @Datetime - @LocalTimeOffset
    RETURN (SELECT DATEADD(second,@AdjustedLocalDatetime, CAST('1970-01-01 00:00:00' AS datetime)))
END;
GO