案例表达过于复杂

时间：2019-04-08 07:08:43

标签： sql sql-server case

我需要创建一个包含下一个适用日期的有效数据集。根据某些参数，这将需要在一周的某一天进行，但可能不止一个工作日。为了确保选择下一个日期，我整理了一个嵌套的case语句。

一些示例数据：

Job:
+----+-------------+----------+----------+----------+
| ID | SERV_PERIOD | SERV_SUN | SERV_MON | SERV_TUE |
+----+-------------+----------+----------+----------+
|  1 | W           | Y        | N        | N        |
|  2 | W           | N        | N        | Y        |
|  3 | W           | Y        | N        | Y        |
|  4 | W           | N        | Y        | Y        |
|  5 | F           | Y        | N        | N        |
|  6 | F           | N        | N        | Y        |
|  7 | F           | Y        | N        | Y        |
|  8 | F           | N        | Y        | Y        |
+----+-------------+----------+----------+----------+
Service:
+----+--------+------------+
| ID | JOB_ID |    DATE    |
+----+--------+------------+
|  1 |      1 | 2019-24-03 |
|  2 |      2 | 2019-26-03 |
|  3 |      3 | 2019-24-03 |
|  4 |      4 | 2019-26-03 |
|  5 |      5 | 2019-24-03 |
|  6 |      6 | 2019-26-03 |
|  7 |      7 | 2019-24-03 |
|  8 |      8 | 2019-26-03 |
+----+--------+------------+
Desired result: (one NextServiceDate for each Job)
+--------+-------------------------------+
| JOB.ID |        NextServiceDate        |
+--------+-------------------------------+
|      1 | 2019-31-03 (the next Sunday)  |
|      2 | 2019-02-04 (the next Tuesday) |
|      3 | 2019-26-03 (the next Tuesday) |
|      4 | 2019-01-04 (the next Monday)  |
|      5 | 2019-07-04 (2 Sundays ahead)  |
|      6 | 2019-09-04 (2 Tuesdays ahead) |
|      7 | 2019-02-04 (the next Tuesday) |
|      8 | 2019-08-04 (2 Mondays ahead)  |
+--------+-------------------------------+

因为可以使用多个工作日，所以检查其有效性的顺序很重要：如果Job 3首先检查SERV_SUN，则发现星期日有效，因此选择下一个星期日日期，将错过26日星期二。工作可以每周一次或每两周一次的事实增加了额外的复杂性。

不足为奇的是，案例陈述中的以下怪物被认为太深了：

CASE 
    WHEN J.SERV_PERIOD = 'W' THEN CASE
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 1 THEN CASE
            WHEN SERV_MON = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 2 THEN CASE
            WHEN SERV_TUE = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 3 THEN CASE
            WHEN SERV_WED = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 4 THEN CASE
            WHEN SERV_THU = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 5 THEN CASE
            WHEN SERV_FRI = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 6 THEN CASE
            WHEN SERV_SAT = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 7 THEN CASE
            WHEN SERV_SUN = Y THEN DATEADD(DD,1,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,2,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,3,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,4,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,5,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,6,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,7,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
    WHEN J.SERV_PERIOD = 'F' THEN CASE
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 1 THEN CASE
            WHEN SERV_MON = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 2 THEN CASE
            WHEN SERV_TUE = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 3 THEN CASE
            WHEN SERV_WED = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 4 THEN CASE
            WHEN SERV_THU = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 5 THEN CASE
            WHEN SERV_FRI = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 6 THEN CASE
            WHEN SERV_SAT = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SUN = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
        WHEN DATEPART(DW,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID)) = 7 THEN CASE
            WHEN SERV_SUN = Y THEN DATEADD(DD,8,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_MON = Y THEN DATEADD(DD,9,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_TUE = Y THEN DATEADD(DD,10,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_WED = Y THEN DATEADD(DD,11,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_THU = Y THEN DATEADD(DD,12,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_FRI = Y THEN DATEADD(DD,13,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
            WHEN SERV_SAT = Y THEN DATEADD(DD,14,(SELECT MAX(DATE) FROM SERVICE WHERE JOB_ID = J.ID))
END AS NextServiceDate

我必须以不同的顺序浏览SERV_字段，具体取决于最后一次服务执行的工作日，以便避免跳过有效日期。如何避免这个问题？我缺少一种更简单的方法吗？

尽管我的错误与this one相同，但我没有找到一种消除嵌套的方法，就像那里的解决方案一样。

3 个答案:

答案 0 :(得分：3)

分解它，构建一些CTE来帮助您达到目标：

declare @Job table (ID int,Serv_Period char(1), Serv_Sun char(1),
                           Serv_mon char(1), Serv_Tue char(1))
insert into @Job(ID,SERV_PERIOD,SERV_SUN,SERV_MON,SERV_TUE) values
(1,'W','Y','N','N'),
(2,'W','N','N','Y'),
(3,'W','Y','N','Y'),
(4,'W','N','Y','Y')
declare @Service table (ID int, Job_id int, Date date)
insert into @Service(ID,JOB_ID,DATE) values
(1,1,'20190324'),
(2,2,'20190326'),
(3,3,'20190324'),
(4,4,'20190326')
--Desired result:
--+--------+-------------------------------+
--| JOB.ID |        NextServiceDate        |
--+--------+-------------------------------+
--|      1 | 2019-31-03 (the next Sunday)  |
--|      2 | 2019-02-04 (the next Tuesday) |
--|      3 | 2019-26-03 (the next Tuesday) |
--|      4 | 2019-01-04 (the next Monday)  |
--+--------+-------------------------------+

;With Recent as (
    select Job_ID,MAX(Date) as Recent from @Service group by Job_ID
), Numbers as (
    select 1 as n union all select 2 union all select 3 union all
    select 4 union all select 5 union all select 6 union all select 7
), Possibles as (
    select
        Job_ID,DATEADD(day,n,Recent) as PossibleDate
    from
        Recent r
            cross join
        Numbers n
    --Where clause if it's a real numbers table
)
select
    j.ID,
    MIN(PossibleDate)
from
    @Job j
        inner join
    Possibles p
        on
            j.ID = p.Job_id
where
    (j.Serv_Sun = 'Y' and DATEPART(weekday,PossibleDate) = DATEPART(weekday,'20150104')) or
    (j.Serv_Mon = 'Y' and DATEPART(weekday,PossibleDate) = DATEPART(weekday,'20150105')) or
    (j.Serv_Tue = 'Y' and DATEPART(weekday,PossibleDate) = DATEPART(weekday,'20150106'))
group by j.ID

结果：

ID          
----------- ----------
1           2019-03-31
2           2019-04-02
3           2019-03-26
4           2019-04-01

那么，我们该怎么办？ Recent仅找到我们的开始日期。 Numbers为我们提供1到7之间的数字（如果您的系统中有实数表，请跳过该数字）。

PossibleDates结合起来将这些天加到Recent中。

然后我们将其加入到工作表中，过滤出所有满足服务条件的行，然后（通过GROUP BY和MIN）选择这些日期最早是我们的结果。

最后，我通过比较“已知的良好”日期来过滤工作日。我这样做是为了避免对当前DATEFIRST设置的依赖。

您可以通过设置多个CTE来扩展此范围，每种服务期限各一个，并根据该期限LEFT JOIN对其进行分类。

答案 1 :(得分：1)

步骤1

摆脱重复的子查询：

 /* same case with MAX_DATE instead of subquery */
FROM ...
CROSS APPLY (SELECT MAX(DATE) MAX_DATE FROM SERVICE WHERE JOB_ID = J.ID) d

可能的版本

FROM ...
INNER JOIN (SELECT MAX(DATE) MAX_DATE, JOB_ID FROM SERVICE S GROUP BY S.JOB_ID) d
ON D.JOB_ID = J.ID

如果要对单个作业执行此操作-如果要对所有作业都选择版本1，则首选版本2。

步骤2

根据嵌套案例系统化基本算术：

;WITH cteJobs As (
SELECT
    CASE
        WHEN SERV_MON = 'Y' THEN 1
        WHEN SERV_TUE = 'Y' THEN 2
        WHEN SERV_WED = 'Y' THEN 3
        WHEN SERV_THU = 'Y' THEN 4
        WHEN SERV_FRI = 'Y' THEN 5
        WHEN SERV_SAT = 'Y' THEN 6
        WHEN SERV_SUN = 'Y' THEN 7
    END DW,
    *
    FROM JOBS J
)
SELECT
    CASE
       WHEN J.SERV_PERIOD = 'W' THEN
          CASE 
          WHEN DATEPART(DW, d.MAX_DATE) >= j.DW 
          /* "fill" till the end of week, then add supported DW */
          THEN DATEADD(DD, 7 - DATEPART(DW, d.MAX_DATE) + j.DW + 1, d.MAX_DATE)
          /* add delta between last date (Mon) and next avail date within this week (Tue) (delta = 1) */
          ELSE DATEADD(DD, j.DW - DATEPART(DW, d.MAX_DATE) + 1, d.MAX_DATE)
          END
       WHEN J.SERV_PERIOD = 'F' THEN
           ...
    END NextServiceDate
FROM cteJobs J
CROSS APPLY (SELECT MAX(DATE) MAX_DATE FROM SERVICE WHERE JOB_ID = J.ID) d

步骤3

还将SERV_PERIOD转换为数字：

;WITH cteJobs As (
SELECT
    CASE
        WHEN SERV_MON = 'Y' THEN 1
        WHEN SERV_TUE = 'Y' THEN 2
        WHEN SERV_WED = 'Y' THEN 3
        WHEN SERV_THU = 'Y' THEN 4
        WHEN SERV_FRI = 'Y' THEN 5
        WHEN SERV_SAT = 'Y' THEN 6
        WHEN SERV_SUN = 'Y' THEN 7
    END DW,
    CASE
       WHEN SERV_PERIOD = 'W' THEN 1
       WHEN SERV_PERIOD = 'F' THEN 8
    END SERV_PERIOD_INC,
    *
    FROM JOB J
)
SELECT
   J.*,
   d.MAX_DATE LastServiceDate,
   DATEPART(DW, d.MAX_DATE) LastWeekDay,
   CASE 
       /* if no avail date within this week */
       WHEN DATEPART(DW, d.MAX_DATE) >= j.DW 
       THEN DATEADD(DD, 7 - DATEPART(DW, d.MAX_DATE) + j.DW + J.SERV_PERIOD_INC, d.MAX_DATE)
       ELSE DATEADD(DD, j.DW - DATEPART(DW, d.MAX_DATE) + J.SERV_PERIOD_INC, d.MAX_DATE)
   END NextServiceDate,
   DATEPART(DW, CASE 
       WHEN DATEPART(DW, d.MAX_DATE) >= j.DW 
       THEN DATEADD(DD, 7 - DATEPART(DW, d.MAX_DATE) + j.DW + J.SERV_PERIOD_INC, d.MAX_DATE)
       ELSE DATEADD(DD, j.DW - DATEPART(DW, d.MAX_DATE) + J.SERV_PERIOD_INC, d.MAX_DATE)
   END) NextWeekDay,
   J.SERV_PERIOD_INC
FROM cteJobs J
INNER JOIN (SELECT MAX(DATE) MAX_DATE, JOB_ID FROM SERVICE S GROUP BY S.JOB_ID) d
ON D.JOB_ID = J.ID

步骤4

标准化您的数据以停止查找可用日期列表：

;WITH cteJobs AS (
  SELECT
    d_norm.DW_NUM AS DW,
    CASE
       WHEN SERV_PERIOD = 'W' THEN 1
       WHEN SERV_PERIOD = 'F' THEN 8
    END SERV_PERIOD_INC,
    *
    FROM JOB J
    CROSS APPLY (
      SELECT 1 AS DW_NUM
      WHERE J.SERV_MON = 'Y'
      UNION ALL
      SELECT 2
      WHERE J.SERV_TUE = 'Y'
      UNION ALL
      SELECT 3
      WHERE J.SERV_WED = 'Y'
      UNION ALL
      SELECT 4
      WHERE J.SERV_THU = 'Y'
      UNION ALL
      SELECT 5
      WHERE J.SERV_FRI = 'Y'
      UNION ALL
      SELECT 6
      WHERE J.SERV_SAT = 'Y'
      UNION ALL
      SELECT 7
      WHERE J.SERV_SUN = 'Y' 
    ) d_norm
)
SELECT
   J.ID JOB_ID,
   d.MAX_DATE LastServiceDate,
   MIN(CASE 
       WHEN DATEPART(DW, d.MAX_DATE) >= j.DW 
       THEN DATEADD(DD, 7 - DATEPART(DW, d.MAX_DATE) + j.DW + J.SERV_PERIOD_INC, d.MAX_DATE)
       ELSE DATEADD(DD, j.DW - DATEPART(DW, d.MAX_DATE) + J.SERV_PERIOD_INC, d.MAX_DATE)
   END) NextServiceDate
FROM cteJobs J
INNER JOIN (SELECT MAX(DATE) MAX_DATE, JOB_ID FROM SERVICE S GROUP BY S.JOB_ID) d
ON D.JOB_ID = J.ID
GROUP BY J.ID, d.MAX_DATE
ORDER BY J.ID

这可以修复您的代码，并可以找到最接近的可用日期。考虑标准化您的数据模型。可用日期应该是行，而不是列。

done 

| JOB_ID | LastServiceDate | NextServiceDate |
|--------|-----------------|-----------------|
|      1 |      2019-03-24 |      2019-03-31 |
|      2 |      2019-03-26 |      2019-04-02 |
|      3 |      2019-03-24 |      2019-03-26 |
|      4 |      2019-03-26 |      2019-04-01 |
|      5 |      2019-03-24 |      2019-04-07 |
|      6 |      2019-03-26 |      2019-04-09 |
|      7 |      2019-03-24 |      2019-04-02 |
|      8 |      2019-03-26 |      2019-04-08 |

答案 2 :(得分：0)

虽然Damian The Unbeliever's answer和Ivan Starostin's answer都进行了一些改进，以使查询更高效，更易读，但问题的原因是内部嵌套{{1} }语句未关闭。

整理CTE（按照他们的建议）使查询本身更具可读性，并且使用Damian的CASE和CROSS JOIN文字数字来减少占用的空间，甚至可以做更多。不过，您仍然可以使用大小合适的UNION语句作为子查询或CTE；尽管它冗长而费力，但实际上并没有很多层次，如果使用正确的语法，它也可以正常工作：

CASE

请注意;WITH cteLastService AS ( SELECT MAX(DATE) AS LastServiceDate, JOB_ID FROM SERVICE GROUP BY SERVICE.JOB_ID ), cteWeekly AS ( SELECT CASE J.SERV_PERIOD WHEN 'F' THEN 7 ELSE NULL END AS 'WeekDayAdd', ID FROM JOB AS J ), cteNextService AS ( SELECT CASE WHEN J.SERV_PERIOD IN ('W','F') THEN CASE WHEN DATEPART(DW,S.LastServiceDate) = 1 THEN CASE WHEN SERV_MON = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 2 THEN CASE WHEN SERV_TUE = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 3 THEN CASE WHEN SERV_WED = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 4 THEN CASE WHEN SERV_THU = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 5 THEN CASE WHEN SERV_FRI = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 6 THEN CASE WHEN SERV_SAT = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SUN = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END WHEN DATEPART(DW,S.LastServiceDate) = 7 THEN CASE WHEN SERV_SUN = 'Y' THEN DATEADD(DD,1 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_MON = 'Y' THEN DATEADD(DD,2 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_TUE = 'Y' THEN DATEADD(DD,3 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_WED = 'Y' THEN DATEADD(DD,4 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_THU = 'Y' THEN DATEADD(DD,5 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_FRI = 'Y' THEN DATEADD(DD,6 + W.WeekDayAdd,S.LastServiceDate) WHEN SERV_SAT = 'Y' THEN DATEADD(DD,7 + W.WeekDayAdd,S.LastServiceDate) END END END AS 'NextServiceDate', J.ID FROM JOB AS J INNER JOIN cteLastService AS S ON S.JOB_ID = J.ID INNER JOIN cteWeekly AS W ON W.ID = J.ID ) 关键字-如果没有关键字，原始语句嵌套的深度为 17个级别 。仅有它们的 3 。在这种情况下，良好的缩进可以使它看起来井井有条，但是却不会告诉每个段要关闭...这意味着将它们放在一起就这么简单：

END
相关问题
最新问题