具有不同查询的SQL动态列

Question

我正在使用Microsoft SQL Server2008。我有一些非常特殊的任务，我真的希望你们能在此方面为我提供帮助，而且这在技术上是可能的...

每个人都有自己的讲座，可以选择一条等待线路，以便可以在等待名单中注册。 等待线必须是动态的。 这样，对于每一次大会，我都可以说我有2条电话或者3或4条电话，依此类推。

我需要的概述是与人有关的每条等待线的一列，相对于当前日期时间为“演讲开始日期”。 所有以过去为起点的讲座均应忽略。

我已经为该http://sqlfiddle.com/#!3/120ef创建了一个sqlfiddle

如果小提琴被更改或损坏，这里是结构，数据和选择。 http://filex02.mcon-mannheim.de/public.php?service=files&t=da4e6fc71cdf30804cb5f51b843ce368

对于每个车道，我都可以使用这样的查询（您可以将其用作小提琴）

所以对于所有等待的行，我需要这样的4个查询

SELECT p.Firstname+' '+p.Lastname as Lane1 --, * 
FROM WaitingLine    wLine 
    JOIN WaitingList wList ON wLine.WaitingLaneID = wList.WaitingLineID 
    JOIN Person p ON wList.PersonID = p.PersonID 
    JOIN Lecture l ON wList.LectureID = l.LectureID 
WHERE wLine.Name = 'Lane1'  AND l.StartDate > GETDATE() 
                                AND wList.Called = 0 
ORDER BY l.StartDate
ASC;

SELECT p.Firstname+' '+p.Lastname as Lane2 --, * 
FROM WaitingLine  wLine 
    JOIN WaitingList wList ON wLine.WaitingLineID =  wList.WaitingLineID 
    JOIN Person p ON wList.PersonID = p.PersonID 
    JOIN Lecture l ON wList.LectureID = l.LectureID 
WHERE wLine.Name = 'Lane2'  AND l.StartDate > GETDATE() 
                            AND wList.Called = 0 
ORDER BY l.StartDate ASC;

SELECT p.Firstname+' '+p.Lastname as Lane3 --, * 
FROM WaitingLine wLine 
    JOIN WaitingList wList ON wLine.WaitingLineID = wList.WaitingLineID 
    JOIN Person p ON wList.PersonID = p.PersonID 
    JOIN Lecture l ON wList.LectureID = l.LectureID 
WHERE wLine.Name = 'Lane3' AND l.StartDate > GETDATE() 
                           AND wList.Called = 0 
ORDER BY l.StartDate ASC;

SELECT p.Firstname+' '+p.Lastname as Lane4 --, * 
FROM WaitingLine wLine 
    JOIN WaitingList wList ON wLine.WaitingLineID = wList.WaitingLineID 
    JOIN Person p ON wList.PersonID = p.PersonID 
    JOIN Lecture l ON wList.LectureID = l.LectureID 
WHERE wLine.Name = 'Lane4' AND l.StartDate > GETDATE() 
                           AND wList.Called = 0 
ORDER BY l.StartDate  ASC;

您可以在这里看到此查询的结果：

我需要的只是一个单独的语句，其结果如下：

请注意 ，带内容的通道都不应该以NULL开头。 所有名称都需要在其演讲的开始/开始日期之前进行排序，并且输出应在每列的第一行中开始

这是我使用的表：

表： WaitingLine

表： WaitingList

表： 人

http://img829.imageshack.us/img829/194/u67b.png

表： 讲座

http://img607.imageshack.us/img607/7520/1tap.png

谢谢

Answer 1

如果需要使用动态列获取结果，则需要恢复为动态查询创建。 请尝试以下查询：

询问

Declare @Values as nvarchar(max)
DECLARE @query  AS NVARCHAR(MAX)
Select @values = COALESCE(@Values + ',', '') + name FROM 
      (select distinct Name from   WaitingLine) as t order by Name

 Select @query = 'SELECT  * ' +' from (SELECT   wline.Name, FirstName+Lastname as who,
 Row_number() over (partition by wline.Name order by l.startdate) as rowX
 FROM WaitingLine    wLine 
 Left outer JOIN WaitingList wList ON wLine.WaitingLineID = wList.WaitingLineID 
 left outer JOIN Person p ON wList.PersonID = p.PersonID 
 left outer join Lecture l ON wList.LectureID = l.LectureID 
 WHERE   (l.StartDate > GETDATE() or l.StartDate is null)
                            AND (wList.Called = 0 or wList.Called is null) ) as t

        pivot 
        (
            max(who)
            for name in ( '+  @values + ')
        ) as p'

execute (@query)

结果

  rowX Lane1     Lane2       Lane3      Lane4
  1    BruceLee  MarcusReis  JohnSmith  NULL
  2    NULL      ChuckNorris JohnDoe    NULL
  3    NULL      BruceLee    SilentBob  NULL
  4    NULL      NULL        BruceLee   NULL

它将为您提供所需的结果，外加一列； 希望不会给您带来麻烦。 在WHERE语句中使用OR的目的是确保您获得了Lane4记录（不包含记录）-但最后，您可以删除条件-无任何后果-我需要检查发生的事情，因此它几乎与您的查询相同。 例如，您可能考虑制作一个View，然后对其进行透视-它也可以工作，并且将使整个解决方案更加紧凑。

Answer 2

下面的查询可以满足您的要求，但是可能会有更优雅和可扩展的实现。 除了您提供的数据集外，我没有在其他任何数据集上进行过测试，我建议您对实际数据进行测试。 我在子查询中留下了多余的字段供您检查数据，但是一旦您满意就应该将其删除。 它们是：-wLine.Name AS Lane和l.StartDate。 话虽这么说，享受！

查询：

SELECT  Lane1, Lane2, Lane3, Lane4
FROM 
(
    SELECT p.Firstname+' '+p.Lastname Lane1, wLine.Name AS Lane, ROW_NUMBER() OVER (ORDER BY l.StartDate) AS rn, l.StartDate
    FROM WaitingLine wLine
    JOIN WaitingList wList ON wLine.WaitingLaneID = wList.WaitingLineID
    JOIN Person p ON wList.PersonID = p.PersonID
    JOIN Lecture l ON wList.LectureID = l.LectureID
    WHERE l.StartDate > GETDATE() 
    AND wList.Called = 0
    AND wLine.Name = 'Lane1'
) Lane1
FULL OUTER JOIN 
(
    SELECT p.Firstname+' '+p.Lastname Lane2, wLine.Name AS Lane, ROW_NUMBER() OVER (ORDER BY l.StartDate) AS rn, l.StartDate
    FROM WaitingLine wLine
    JOIN WaitingList wList ON wLine.WaitingLaneID = wList.WaitingLineID
    JOIN Person p ON wList.PersonID = p.PersonID
    JOIN Lecture l ON wList.LectureID = l.LectureID
    WHERE l.StartDate > GETDATE() 
    AND wList.Called = 0
    AND wLine.Name = 'Lane2'
) Lane2
ON Lane1.rn = Lane2.rn
FULL OUTER JOIN 
(
    SELECT p.Firstname+' '+p.Lastname Lane3, wLine.Name AS Lane, ROW_NUMBER() OVER (ORDER BY l.StartDate) AS rn, l.StartDate
    FROM WaitingLine wLine
    JOIN WaitingList wList ON wLine.WaitingLaneID = wList.WaitingLineID
    JOIN Person p ON wList.PersonID = p.PersonID
    JOIN Lecture l ON wList.LectureID = l.LectureID
    WHERE l.StartDate > GETDATE() 
    AND wList.Called = 0
    AND wLine.Name = 'Lane3'
) Lane3
ON (    Lane1.rn = Lane3.rn
    OR  Lane2.rn = Lane3.rn)
FULL OUTER JOIN 
(
    SELECT p.Firstname+' '+p.Lastname Lane4, wLine.Name AS Lane, ROW_NUMBER() OVER (ORDER BY l.StartDate) AS rn, l.StartDate
    FROM WaitingLine wLine
    JOIN WaitingList wList ON wLine.WaitingLaneID = wList.WaitingLineID
    JOIN Person p ON wList.PersonID = p.PersonID
    JOIN Lecture l ON wList.LectureID = l.LectureID
    WHERE l.StartDate > GETDATE() 
    AND wList.Called = 0
    AND wLine.Name = 'Lane4'
) Lane4
ON  (   Lane1.rn = Lane4.rn
    OR  Lane2.rn = Lane4.rn
    OR  Lane3.rn = Lane4.rn)

结果：

Lane1       Lane2           Lane3       Lane4
Bruce Lee   Marcus Reis     John Smith  NULL
NULL        Chuck Norris    John Doe    NULL
NULL        Bruce Lee       Silent Bob  NULL
NULL        NULL            Bruce Lee   NULL

按照下面Daniels的回答，要添加动态元素，您可以尝试在另一个查询中构建它，然后使用EXECUTE或sp_execute来运行它，但请记住这种方法有优缺点-我衷心建议您阅读本文 。 这是我对使用sp_executesql的动态sql方法的看法： 查询：

    DECLARE @columns AS NVARCHAR(4000)
SELECT @columns = COALESCE(@columns + ',', '') + name 
FROM  WaitingLine
ORDER BY Name
--SELECT @columns--

DECLARE @stmt AS NVARCHAR(4000)
DECLARE @params nvarchar(4000)
DECLARE @startdate DATETIME
SET @startdate = GETDATE()
SET @params = N'@sd DATETIME'
SET @stmt = N'SELECT  '+@columns+' 
              FROM (SELECT wline.Name AS LaneName
                        , FirstName + '' '' + Lastname AS PersonFullName
                        , Row_number() over (partition by wline.Name order by l.startdate) AS rn
                    FROM WaitingLine    wLine 
                    LEFT JOIN WaitingList wList 
                        ON wLine.WaitingLaneID = wList.WaitingLineID 
                    LEFT JOIN Person p 
                        ON wList.PersonID = p.PersonID 
                    LEFT JOIN Lecture l 
                        ON wList.LectureID = l.LectureID 
                    WHERE   l.StartDate > @sd
                  AND wList.Called = 0) AS src
              PIVOT (MAX(PersonFullName) FOR LaneName IN ('+@columns+')) AS pvt'

EXEC sp_executesql @stmt, @params, @sd=@startdate

结果：

Lane1       Lane2           Lane3       Lane4
Bruce Lee   Marcus Reis     John Smith  NULL
NULL        Chuck Norris    John Doe    NULL
NULL        Bruce Lee       Silent Bob  NULL
NULL        NULL            Bruce Lee   NULL