用零填充 SQL 查询中的日期空白

Question

我有以下结构（来自表之间的一些连接等），将用于生成图表。

某些 ID 没有所有日期的数据，这会导致图表中出现一些虚线。

问题是，如何为每个 ID 添加缺失的日期并用零填充其数据单元格？

作为脚本：

(67, '2016-09-28 00:00:00.000',1),
(178, '2016-09-28 00:00:00.000',6),
(42, '2016-09-25 00:00:00.000',1),
(66, '2016-09-25 00:00:00.000',122),
(67, '2016-09-25 00:00:00.000',2),
(10, '2016-09-24 00:00:00.000',5),
(13, '2016-09-24 00:00:00.000',4),
(66, '2016-09-24 00:00:00.000',198),
(67, '2016-09-24 00:00:00.000',15),
(178, '2016-09-24 00:00:00.000',4),
(10, '2016-09-23 00:00:00.000',1),
(13, '2016-09-23 00:00:00.000',2),
(42, '2016-09-23 00:00:00.000',4),
(66, '2016-09-23 00:00:00.000',208),
(67, '2016-09-23 00:00:00.000',15)

Answer 1

日历表和 CROSS JOIN 的另一种方式：

;WITH YourQueryOutput AS (
--put your select statement here
), calendar AS (
SELECT  CAST(MIN(RoundedTime) as datetime) as d,
        MAX(RoundedTime) as e
FROM YourQueryOutput
UNION ALL
SELECT  DATEADD(day,1,d),
        e
FROM calendar
WHERE d < e
)

SELECT  t.ID,
        c.d,
        COALESCE(t1.[data],0) as [data]
FROM calendar c
CROSS JOIN (
    SELECT DISTINCT ID
    FROM YourQueryOutput
    ) t
LEFT JOIN YourQueryOutput t1
    ON t.ID = t1.ID and t1.RoundedTime = c.d
ORDER BY t.ID, c.d
OPTION(MAXRECURSION 0)

您提供的样本的输出

ID  d                       data
10  2016-09-23 00:00:00.000 1
10  2016-09-24 00:00:00.000 5
10  2016-09-25 00:00:00.000 0
10  2016-09-26 00:00:00.000 0
10  2016-09-27 00:00:00.000 0
10  2016-09-28 00:00:00.000 0
...
178 2016-09-23 00:00:00.000 0
178 2016-09-24 00:00:00.000 4
178 2016-09-25 00:00:00.000 0
178 2016-09-26 00:00:00.000 0
178 2016-09-27 00:00:00.000 0
178 2016-09-28 00:00:00.000 6

Answer 2

这是一种方法：

with t as (
      <your query here>
     )
select i.id, rt.roundedtime, coalesce(data, 0) as data
from (select distinct id from t) i cross join
     (select distinct roundedtime rt from t) rt left join
     t
     on t.id = i.id and t.roundedtime = rt.roundedtime;

换句话说，使用cross join 创建日期列表和ids。然后使用left join 引入您的数据。

此查询对您的原始数据使用 select distinct 来获取日期和 ID 列表。可能有更有效的方法来获取这些列表中的每一个。

Answer 3

您可以在使用 join 的 SELECT 语句中检查 ISNULL(YourDataColumn,0)。

示例：

SELECT
    Q.QuestionId,
    Q.SenderType,
    ISNULL(Q.Data,0) AS Data
FROM @tblQuestion Q
LEFT JOIN @tblTeacher T ON Q.SenderId=T.Id AND Q.SENDERTYPE='TEACHER'
LEFT JOIN @tblInstitute I ON Q.SenderId=I.Id AND Q.SENDERTYPE='INSTITUTE'

如果加入后没有可用数据，则在 Select Statement Data column return 0 上方输入