Sql 如何连接多行中的字符串？

我有一个包含以下列的表：

• 产品
• 年更新

示例数据：

PROD1,2017
PROD1,2015
PROD2,2014
PROD3,2017

如何获取每个产品更新的时间列表？比如：

PRODUCT,2017,2016,2015,2014,etc
PROD1,Y,N,Y,N
PROD2,N,N,N,Y
PROD3,Y,N,N,N

或

甲骨文数据库

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谢谢

我假设该表的名称为

Products

，请将其更改为表的名称

Oracle

您可以使用

listag

来实现它

如果您使用的是SQL Server，则可以这样做

select p.Product + ', ' + stuff((select ', '+ cast(tp.YearUpdated as varchar(4)) from Products tp where p.Product = tp.Product
          FOR XML PATH('')) , 1, 2, '')
from Products p
group by p.Product

如果您想快速测试它，您可以尝试一下（使用内存中的表）

---

假设表中有id和年份列：

   select cast ( t1.id as  varchar) + ',' + ( case when  t1.rn2 = 1   then  '2015' else '' end )
+ 
   ( case when  t1.rn2 = 2  then  '2015,2016 ' else  '' end ) + 
   ( case when  t1.rn2 =  3 then  '2015,2016,2017' else '' end ) 
 from 
  (select distinct  yourTBL.id , max(yourTBL.rn)
   over ( partition by yourTBL.id order by yourTBL.year rows BETWEEN  UNBOUNDED PRECEDING 
        AND UNBOUNDED following ) as rn2
 from (select id ,  year ,  
      row_number()over (partition by id order by year) as rn from yourTBL ) t) t1

---

嗯，很有趣。你试过什么问题？另外，您正在使用什么RDBMS？只是想澄清一下，它在开始时是这样的：

prod12017；Prod12015；2014年4月2日等？RDBMS=Oracle；是的，数据和你的例子相符你一定是在开玩笑。为什么要硬编码字符串？如果表中有2000条记录，年份从1950年到1999年，该怎么办？此外，表中没有Id，问题是清楚地说明表中的列（产品和年份更新）。
select p.Product + ', ' + stuff((select ', '+ cast(tp.YearUpdated as varchar(4)) from Products tp where p.Product = tp.Product
          FOR XML PATH('')) , 1, 2, '')
from Products p
group by p.Product

declare @Products table (Product varchar(50), YearUpdated int);

insert into @Products values ('Product 1', 2000);
insert into @Products values ('Product 1', 2001);
insert into @Products values ('Product 1', 2002);
insert into @Products values ('Product 1', 2003);
insert into @Products values ('Product 2', 2010);
insert into @Products values ('Product 2', 2011);
insert into @Products values ('Product 4', 2012);
insert into @Products values ('Product 4', 2013);
insert into @Products values ('Product 4', 2015);
insert into @Products values ('Product 3', 2005);

select p.Product + ', ' + stuff((select ', '+ cast(tp.YearUpdated as varchar(4)) from @Products tp where p.Product = tp.Product
          FOR XML PATH('')) , 1, 2, '')
from @Products p
group by p.Product

   select cast ( t1.id as  varchar) + ',' + ( case when  t1.rn2 = 1   then  '2015' else '' end )
+ 
   ( case when  t1.rn2 = 2  then  '2015,2016 ' else  '' end ) + 
   ( case when  t1.rn2 =  3 then  '2015,2016,2017' else '' end ) 
 from 
  (select distinct  yourTBL.id , max(yourTBL.rn)
   over ( partition by yourTBL.id order by yourTBL.year rows BETWEEN  UNBOUNDED PRECEDING 
        AND UNBOUNDED following ) as rn2
 from (select id ,  year ,  
      row_number()over (partition by id order by year) as rn from yourTBL ) t) t1