如何从日期范围

Question

我有一个SQL查询：

WITH Cte AS
(
    SELECT DateTime,

        rn1 = ROW_NUMBER() OVER(ORDER BY DateTime ASC),
        rn2 = ROW_NUMBER() OVER(ORDER BY DateTime DESC)
    FROM
        Test
    WHERE
        Username = 'ME'
        AND DateTime > '2016-01-05'
        AND DateTime < '2016-01-06'
)
SELECT * FROM Cte WHERE rn1 = 1 UNION ALL
SELECT * FROM Cte WHERE rn2 = 1

通过此查询，我成功获取 2016年1月5日的第一个和最后一个数据

但是，我怎样才能获得第一个和最后一个数据，例如，从 1月5日到 1月8日？

也就是说，我想从1月5日获得第一个和最后一个数据，然后是1月6日的第一个和最后一个数据，然后是1月7日的第一个和最后一个数据，然后是第一个和第一个数据。最后的数据来自1月8日。

UPDATE

你可以看到，订单有点乱 我希望它看起来像这样

Answer 1

要获取1月5日至8日每天的第一个和最后一个数据，您需要在PARTITION BY条款中添加OVER：

WITH Cte AS(
    SELECT 
        DateTime,
        rn1 = ROW_NUMBER() OVER(PARTITION BY CAST(DateTime AS DATE) ORDER BY DateTime ASC),
        rn2 = ROW_NUMBER() OVER(PARTITION BY CAST(DateTime AS DATE) ORDER BY DateTime DESC)
    FROM Test
    WHERE
        Username = 'ME'
        AND DateTime >= '20160105'
        AND DateTime < '20160109'
)
SELECT * FROM Cte WHERE rn1 = 1 OR rn2 = 1

编辑：

WITH Cte AS(
    SELECT
        CAST(DateTime AS DATE),
        DateTime,
        rn1 = ROW_NUMBER() OVER(PARTITION BY CAST(DateTime AS DATE) ORDER BY DateTime ASC),
        rn2 = ROW_NUMBER() OVER(PARTITION BY CAST(DateTime AS DATE) ORDER BY DateTime DESC)
    FROM Test
    WHERE
        Username = 'ME'
        AND DateTime >= '20160105'
        AND DateTime < '20160109'
)
SELECT * FROM Cte WHERE rn1 = 1 OR rn2 = 1
ORDER BY CAST(DateTime AS DATE)