使用 group by 动态将行转换为列

Question

我正在寻找可以使用分组依据将行转列的代码，下面是我的 table 和想要的输出。

Table:

MR_ID  |  DR_ID
--------|--------
MR_123  |   1
MR_123  |   3
MR_124  |   4
MR_124  |   5
MR_124  |   6
MR_125  |   0

期望输出：

MR_ID  |  DR_ID_1 |  DR_ID_2 | DR_ID_3 
--------|----------|----------|---------
MR_123  |     1    |    2     |   NULL
MR_124  |     4    |    5     |    6
MR_125  |     0    |   NULL   |   NULL

这里我希望每个 DR_ID 的每个单独的列都有数字的增量，这应该是动态的。

Answer 1

这样试试：

DECLARE @mockup TABLE(MR_ID VARCHAR(10),DR_ID INT);
INSERT INTO @mockup VALUES
 ('MR_123',1)
,('MR_123',3)
,('MR_124',4)
,('MR_124',5)
,('MR_124',6)
,('MR_125',0);

SELECT p.*
FROM
(
    SELECT *
          ,'DR_ID_' + CAST(ROW_NUMBER() OVER(PARTITION BY MR_ID ORDER BY DR_ID) AS VARCHAR(MAX)) AS columnName
    FROM @mockup AS m
) AS t
PIVOT(MAX(DR_ID) FOR columnName IN(DR_ID_1,DR_ID_2,DR_ID_3,DR_ID_4)) AS p;

"dynamic column name" 是用 ROW_NUMBER()

创建的

Answer 2

您也可以使用动态 sql 查询。

查询

declare @sql as varchar(max);
select @sql = 'select t.MR_ID, ' + stuff((
    select distinct ', max(case t.[rn] when ' 
    + cast(t.[rn] as varchar(10)) + ' then t.[DR_ID] end) 
    [DR_ID' + cast(t.[rn] as varchar(10)) + ']' 
    from (
        select [rn] = row_number() 
        over(partition by MR_ID order by DR_ID), *
        from your_table_name
    )t
    for xml path('')
), 1, 2, '')
+ ' from (select [rn] = row_number() over(partition by MR_ID order by DR_ID), * 
  from your_table_name)t
  group by t.[MR_ID];';

exec(@sql);

Find a demo here

Answer 3

试试这个，

    create table  #tmp (MR_ID varchar(50),DR_ID int)
insert into  #tmp VALUES
('MR_123', 1),('MR_123', 3),('MR_124', 4),('MR_124', 5)
,('MR_124', 6),('MR_125', 0)

 declare @DRCol varchar(50)
 declare @Prefix varchar(20)='DR_'
 ;With CTE as
 (
select *
,ROW_NUMBER()over(partition by MR_ID order by DR_ID)rn
 from #tmp
 )

 select top 1 
@DRCol=stuff((select ','+'['+@Prefix+cast(rn as varchar)+']' 
 from cte c1 where c.mr_id=c1.mr_id for xml path('')),1,1,'')
 from cte c
 where c.mr_id=(select top 1 mr_id from cte c1 order by rn desc)


 declare @Sql varchar(2000)=''

 set @Sql='   SELECT p.*
FROM
(
  SELECT *
          ,'''+@Prefix+'''+ cast(ROW_NUMBER() OVER(PARTITION BY MR_ID ORDER BY DR_ID) as varchar(max))  columnName
    FROM #tmp AS m
    ) AS t
PIVOT(MAX(DR_ID) FOR columnName IN('+@DRCol+')) AS p'
print @sql
exec(@sql)
drop table #tmp

使用 group by 动态将行转换为列

Dynamic convert Row to Column using group by

sql-server

transpose

group-by