尝试添加 ROW_NUMBER 时是否可以删除此查询中的级联 CTE

Question

我在数据库中有一个阅读清单。我用它作为个人训练的基础它随着时间的推移在功能上有所增长，所以请原谅奇怪的结构。

我正在尝试向该查询添加分页，但由于我在查询中实现“Ord”的方式，我在尝试添加 ROW_NUMBER 方法时遇到了问题。

我能够利用级联通用 Table 表达式来完成这项工作，但我觉得一定有更好的方法。

这是显示作者的所有书籍时输出应该执行的操作：

从最旧到最新显示已完成的书籍
然后显示由“状态”栏控制的当前定义的阅读列表
然后显示该作者未列出的任何其他书籍

设置

CREATE TABLE #books(
    ID int,
    Author nvarchar(100),
    Title nvarchar(100),
    Series nvarchar(100),
    BookNumber int,
    DateCompleted smalldatetime,
    [Status] int
)
INSERT INTO #books (ID, Author, Title, Series, BookNumber, DateCompleted, Status) VALUES 
(1004,'J. K. Rowling','Harry Potter and the Chamber of Secrets','Harry Potter',2,'1-Mar-2020',1),
(1045,'J. K. Rowling','Harry Potter and the Prisoner of Azkaban','Harry Potter',3,NULL,2),
(1047,'J. K. Rowling','Harry Potter and the Goblet of Fire','Harry Potter',4,NULL,3),
(1048,'J. K. Rowling','Harry Potter and the Order of the Pheonix','Harry Potter',5,NULL,4),
(1049,'J. K. Rowling','Harry Potter and the Half Blood Prince','Harry Potter',6,NULL,NULL),
(1051,'J. K. Rowling','Harry Potter and the Deathly Hallows','Harry Potter',7,NULL,NULL),
(1185,'J. K. Rowling','Harry Potter and the Sorcerer''s Stone','Harry Potter',1,'1-Jan2020',NULL)

DECLARE @Author nVarChar(100) = 'J. K. Rowling'
DECLARE @Year nVarChar(5) = ''
DECLARE @PageNum INT = 1;
DECLARE @PageSize INT = 10;

原始查询

SELECT b.ID,
       b.Title,
       b.Series,
       b.BookNumber,
       ISNULL(b.Series, '') + ISNULL(' (book ' + LTRIM(STR(b.BookNumber)) + ')','') as SeriesDesc,
       b.Author,
       Case
            When b.[Status] = 1 Then 'Completed'
            When b.[Status] = 2 Then 'Reading'
            When b.[Status] > 2 Then 'Next'
       End as StatusDesc,
       b.[Status],
       b.DateCompleted,
       CASE 
         WHEN b.DateCompleted is not NULL THEN 0
         WHEN b.[Status] is not NULL THEN 5
         WHEN b.[Status] is NULL THEN 9
       END as Ord
FROM #books b
WHERE (((b.Author = @Author OR @Author = '') AND b.DateCompleted is not NULL) AND
      (Year(b.DateCompleted) = @Year OR @Year = ''))
      OR
      (b.Author = @Author AND b.DateCompleted is NULL AND @Year = '')
ORDER BY Ord, [Status], DateCompleted, Series, BookNumber

这是我能够让它按预期工作的唯一方法。

;WITH Step1 AS
(SELECT b.ID,
       b.Title,
       b.Series,
       b.BookNumber,
       ISNULL(b.Series, '') + ISNULL(' (book ' + LTRIM(STR(b.BookNumber)) + ')','') as SeriesDesc,
       b.Author,
       Case
            When b.[Status] = 1 Then 'Completed'
            When b.[Status] = 2 Then 'Reading'
            When b.[Status] > 2 Then 'Next'
       End as StatusDesc,
       b.[Status],
       b.DateCompleted,
       CASE 
         WHEN b.DateCompleted is not NULL THEN 0
         WHEN b.[Status] is not NULL THEN 5
         WHEN b.[Status] is NULL THEN 9
       END as Ord
FROM #books b
WHERE (((b.Author = @Author OR @Author = '') AND b.DateCompleted is not NULL) AND
      (Year(b.DateCompleted) = @Year OR @Year = ''))
      OR
      (b.Author = @Author AND b.DateCompleted is NULL AND @Year = '')
),
Step2 AS
(SELECT ID, Title, Series, BookNumber, SeriesDesc, Author, StatusDesc, [Status], DateCompleted, Ord,
ROW_NUMBER() OVER (ORDER BY Ord, [Status], DateCompleted, Series, BookNumber) as RowNum
FROM Step1)

SELECT
    ID, Title, Series, BookNumber, SeriesDesc, Author, StatusDesc, [Status], DateCompleted, Ord, RowNum
FROM Step2
WHERE @PageNum = 0 OR (RowNum BETWEEN (@PageNum - 1) * @PageSize + 1 
                       AND @PageNum * @PageSize)
ORDER BY RowNum

预期输出

|---------------------|-------------------------------------------|---------------------|------------------|-----------------------|------------------|---------------------|------------------|---------------------|------------------|
|       ID            |                   Title                   |       Series        |   BookNumber     |      SeriesDesc       |    Author        |     StatusDesc      |     Status       |   DateCompleted     |       Ord        |
|---------------------|-------------------------------------------|---------------------|------------------|-----------------------|------------------|---------------------|------------------|---------------------|------------------|
|      1185           | Harry Potter and the Sorcerer's Stone     |    Harry Potter     |        1         | Harry Potter (book 1) |  J. K. Rowling   |        NULL         |       NULL       | 2020-01-01 00:00:00 |        0         |
|      1185           | Harry Potter and the Chamber of Secrets   |    Harry Potter     |        2         | Harry Potter (book 2) |  J. K. Rowling   |     Completed       |        1         | 2020-03-01 00:00:00 |        0         |
|      1185           | Harry Potter and the Prisoner of Azkaban  |    Harry Potter     |        3         | Harry Potter (book 3) |  J. K. Rowling   |      Reading        |        2         |        NULL         |        5         |
|      1185           | Harry Potter and the Goblet of Fire       |    Harry Potter     |        4         | Harry Potter (book 4) |  J. K. Rowling   |        Next         |        3         |        NULL         |        5         |
|      1185           | Harry Potter and the Order of the Pheonix |    Harry Potter     |        5         | Harry Potter (book 5) |  J. K. Rowling   |        Next         |        4         |        NULL         |        5         |
|      1185           | Harry Potter and the Half Blood Prince    |    Harry Potter     |        6         | Harry Potter (book 6) |  J. K. Rowling   |        NULL         |       NULL       |        NULL         |        9         |
|      1185           | Harry Potter and the Deathly Hallows      |    Harry Potter     |        7         | Harry Potter (book 7) |  J. K. Rowling   |        NULL         |       NULL       |        NULL         |        9         |
|---------------------|-------------------------------------------|---------------------|------------------|-----------------------|------------------|---------------------|------------------|---------------------|------------------|

Answer 1

那么获取偏移量如何：

SELECT b.ID,
       b.Title,
       b.Series,
       b.BookNumber,
       ISNULL(b.Series, '') + ISNULL(' (book ' + LTRIM(STR(b.BookNumber)) + ')','') as SeriesDesc,
       b.Author,
       Case
            When b.[Status] = 1 Then 'Completed'
            When b.[Status] = 2 Then 'Reading'
            When b.[Status] > 2 Then 'Next'
       End as StatusDesc,
       b.[Status],
       b.DateCompleted,
       CASE 
         WHEN b.DateCompleted is not NULL THEN 0
         WHEN b.[Status] is not NULL THEN 5
         WHEN b.[Status] is NULL THEN 9
       END as Ord
FROM #books b
WHERE (((b.Author = @Author OR @Author = '') AND b.DateCompleted is not NULL) AND
      (Year(b.DateCompleted) = @Year OR @Year = ''))
      OR
      (b.Author = @Author AND b.DateCompleted is NULL AND @Year = '')
ORDER BY Ord, [Status], DateCompleted, Series, BookNumber
OFFSET  @PageSize*@PageNum ROWS
FETCH NEXT @PageSize ROWS ONLY

@PageNum 应该从 0

开始

尝试添加 ROW_NUMBER 时是否可以删除此查询中的级联 CTE

Is it possible to remove cascading CTEs in this query when trying to add ROW_NUMBER

sql

sql-server

common-table-expression