获得包含所有孩子的单亲父母

时间：2009-12-24 11:51:29

标签： sql-server sql-server-2005 pivot

让我假设我在SQL（server 2005）中设置了父子结构：

CREATE TABLE parent (Id INT IDENTITY PRIMARY KEY, Name VARCHAR(255))
CREATE TABLE child (Id INT IDENTITY PRIMARY KEY, parentId INT, Name VARCHAR(255))

insert into parent select 'parent with 1 child'
insert into parent select 'parent with 2 children'

insert into child(name, parentid) select 'single child of parent 1', 1
insert into child(name, parentid) select 'child 1 of 2 of parent 2', 2
insert into child(name, parentid) select 'child 2 of 2 of parent 2', 2

有没有办法在每个父级返回一行，并将其子项作为列？像：

parent.Id，parent.Name，child（1）.Id，child（1）.Name，child（2）.Id，child（2）.Name

开始于：

select * from parent p
    left outer join child c1 on c1.parentid = p.id

5 个答案:

答案 0 :(得分：4)

你的例子接近于旋转，但我不认为枢轴功能在这个上是可用的。

我已将您的示例重命名为使用“部门人”而不是“儿童父母”，只是为了保持理智。

所以，第一张表和一些数据

DECLARE @Department TABLE
  ( 
   DepartmentID int
  ,DepartmentName varchar(50)
  )
DECLARE @Person TABLE
  ( 
   PersonID int
  ,PersonName varchar(50)
  ,DepartmentID int
  )

INSERT  INTO @Department
  ( DepartmentID, DepartmentName )
 SELECT 1, 'Accounting' UNION
 SELECT 2, 'Engineering' UNION
 SELECT 3, 'Sales' UNION
 SELECT 4, 'Marketing' ;

INSERT  INTO @Person
  ( PersonID, PersonName, DepartmentID )
 SELECT 1, 'Lyne', 1 UNION
 SELECT 2, 'Damir', 2 UNION
 SELECT 3, 'Sandy', 2 UNION
 SELECT 4, 'Steve', 3 UNION
 SELECT 5, 'Brian', 3 UNION
 SELECT 6, 'Susan', 3 UNION
 SELECT 7, 'Joe', 4 ;

现在我想要展平模型，我会使用临时表因为我有表变量 - 但是对“真实表”的观点也会很好。

/*  Create a table with:
    DepartmentID, DepartmentName, PersonID, PersonName, PersonListIndex

 This could be a view instead of temp table. 
*/
IF object_id('tempdb.dbo.#tmpTbl','U') IS NOT NULL
 DROP TABLE #tmpTbl

;
WITH  prs
        AS ( SELECT PersonID
                   ,PersonName
                   ,DepartmentID
                   ,row_number() OVER ( PARTITION BY DepartmentID ORDER BY PersonID ) AS [PersonListIndex]
             FROM   @Person
           ),
      dptprs
        AS ( SELECT d.DepartmentID
                   ,d.DepartmentName
                   ,p.PersonID 
                   ,p.PersonName
                   ,p.PersonListIndex
             FROM   @Department AS d
                    JOIN prs AS p ON p.DepartmentID = d.DepartmentID
           )
SELECT * INTO #tmpTbl FROM dptprs

-- SELECT * FROM #tmpTbl

动态列表示动态查询，我会逐行将其组成表

/* Table to compose dynamic query */
DECLARE @qw TABLE
  ( 
   id int IDENTITY(1, 1)
  ,txt nvarchar(500)
  )

/* Start composing dynamic query */
INSERT  INTO @qw ( txt ) VALUES  ( 'SELECT' ) 
INSERT  INTO @qw ( txt ) VALUES  ( '[DepartmentID]' )
INSERT  INTO @qw ( txt ) VALUES  ( ',[DepartmentName]' ) ;


/* fetch max number of employees in a department */
DECLARE @i int ,@m int
SET @m = (SELECT max(PersonListIndex) FROM #tmpTbl)

/* Compose dynamic query */
SET @i = 1
WHILE @i <= @m 
  BEGIN  
      INSERT  INTO @qw ( txt )
            SELECT  ',MAX(CASE [PersonListIndex] WHEN '
                    + cast(@i AS varchar(10)) + ' THEN [PersonID] ELSE NULL END) AS [Person_'
                    + cast(@i AS varchar(10)) + '_ID]'

      INSERT  INTO @qw ( txt )
            SELECT  ',MAX(CASE [PersonListIndex] WHEN '
                    + cast(@i AS varchar(10)) + ' THEN [PersonName] ELSE NULL END) AS [Person_'
                    + cast(@i AS varchar(10)) + '_Name]'  

    SET @i = @i + 1
  END

/* Finish the dynamic query */
INSERT  INTO @qw (txt) VALUES ( 'FROM #tmpTbl' )
INSERT  INTO @qw (txt) VALUES ( 'GROUP BY [DepartmentID], [DepartmentName]' )
INSERT  INTO @qw (txt) VALUES ( 'ORDER BY [DepartmentID]' )

-- SELECT * FROM @qw

现在，将所有查询行连接到一个变量并执行

/* Create a variable with dynamic sql*/
DECLARE @exe nvarchar(4000)
SET @exe=''
SELECT  @exe = @exe + txt + ' ' FROM @qw ORDER BY id

/* execute dynamic sql */
EXEC master..sp_executesql @exe

结果如下：

alt text

答案 1 :(得分：3)

如果你想要一个不同的外观，试试这个

示例数据 

declare @parent table (Id INT IDENTITY PRIMARY KEY, Name VARCHAR(255))
declare  @child table (Id INT IDENTITY PRIMARY KEY, parentId INT, Name VARCHAR(255))

insert into @parent select 'parent with 1 child'
insert into @parent select 'parent with 2 children'
insert into @child(name, parentid) select 'single child of parent 1', 1
insert into @child(name, parentid) select 'child 1 of 2 of parent 2', 2
insert into @child(name, parentid) select 'child 2 of 2 of parent 2', 2

<强>查询 

select p.Id as ParentId,p.Name as ParentName
    ,stuff((select ',  ' + 'child(' + cast(c.Id as varchar(10)) + ') : ' +  c.Name 
    from @child c where c.parentId = p.id for xml path('')),1,1,'') 'Child(id):Child Names'
    from @parent p
group by
p.Id,p.Name

<强>输出 

ParentId    ParentName  Child(id):Child Names
1   parent with 1 child   child(1) : single child of parent 1
2   parent with 2 children    child(2) : child 1 of 2 of parent 2,  child(3) : child 2 of 2 of parent 2

答案 2 :(得分：1)

look at the pivot functionality if you use sql server 2005

答案 3 :(得分：1)

尝试动态旋转

测试数据 

declare @parent table (Id INT IDENTITY PRIMARY KEY, Name VARCHAR(255))
declare  @child table (Id INT IDENTITY PRIMARY KEY, parentId INT, Name VARCHAR(255))

insert into @parent select 'parent with 1 child'
insert into @parent select 'parent with 2 children'
insert into @child(name, parentid) select 'single child of parent 1', 1
insert into @child(name, parentid) select 'child 1 of 2 of parent 2', 2
insert into @child(name, parentid) select 'child 2 of 2 of parent 2', 2

<强>查询 

declare @col_list varchar(max)
declare @dynquery nvarchar(max)
select
 c.Id as ChildId
 , p.Id as ParentId
 ,p.Name as ParentName
 ,c.Name as ChildName 
into #t from @parent p join @child c on p.Id = c.parentId 
select @col_list = stuff(cols,1,1,'') from
(select distinct ',[' + cast(ChildName as varchar(50)) + ']' 
 from #t for xml path(''))X(cols)
set @dynquery = 'select * from #t pivot ( max(ChildId) for ChildName in (' + @col_list + ') ' + ') as pvt'
EXEC  master..sp_executesql @dynquery 
drop table #t

<强>输出： 

ParentId ParentName child 1 of 2 of parent 2 child 2 of 2 of parent 2 single child of parent 1
1 parent with 1 child NULL NULL 1
2 parent with 2 children 2 3 NULL

答案 4 :(得分：1)

在看了Damir Sudarevic的回答后，我想出了这个:(参见我对表结构的质疑）

declare @family table (parentid int , parentname varchar(255), child1id int, child1name varchar(255), child2id int, child2name varchar(255))

insert into @family(parentid, parentname)
select id, name from parent

update @family set child1id = c.id, child1name = c.name
from @family f, child c 
where c.parentid = f.parentid

update @family set child2id = c.id, child2name = c.name
from @family f, child c 
where c.parentid = f.parentid
and not exists
    (select child1id from @family where child1id = c.id)

select * from @family
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