将多行连接成一行 [英] Concatenate multiple rows into one row

问题描述

我刚刚在 SQL Server 上学习 SQL.我需要将多行连接成一列.我寻找了一些示例，但没有找到可以满足我需求的示例.

I am just now learning SQL on SQL Server. I need to concatenate multiple rows into one column. I have looked for examples, but do not find one that I can use to suit my needs.

Country     ProjectTA   Complexity TID  Sites   Inits   Name
United States A8022 Obesity Low  4692   69  JT  AD
United States A8022 Obesity Low  4692   69  jpni    CBM Budget
United States A8022 Obesity Low  4692   69  PIHR    AD
United States A8022 Obesity Low  4692   69  jpni    CBM Budget
United States A8022 Obesity Low  4692   69  hale    ePublishing Group
United States S8033 CNS Medium   5423   69  ShyP    CBM Payment
United States S8033 CNS Medium   5423   69  dedu    ePublishing Group
United States S8033 CNS Low  5423   69  AHrp    ePublishing Group

我想按名称连接行并用,"列出初始化

I want to concatenate rows by Name and have Inits listed with ','

United States A8022 Obesity Low 4692    69 JT,PIHR  AD
United States A8022 Obesity Low 4692    69 jpni, PIHR   CBM Budget
United States A8022 Obesity Low 4692    69 hale          ePublishing Group
United States S8033 CNS Medium  5423    69 ShyP          CBM Payment
United States S8033 CNS Medium  5423    69 dedu, Ahrp   ePublishing Group

任何帮助将不胜感激.非常感谢.

Any help would be appreciated. Thanks so much.

推荐答案

不幸的是 SQL Server 没有一个简单的函数来生成逗号分隔的列表，你必须实现 FOR XML PATH 才能得到清单.

Unfortunately SQL Server does not have an easy function to generate a comma separated list, you will have to implement FOR XML PATH to get the list.

有几种方法可以做到这一点，您可以使用STUFF 和FOR XML PATH:

There are a few ways to do this, you can use STUFF and FOR XML PATH:

select distinct t1.country,
  t1.ProjectTA, 
  t1.Complexity,
  t1.TID,
  t1.Sites,
  STUFF(
         (SELECT ', ' + t2.Inits
          FROM yt t2
          where t1.Country = t2.Country
            and t1.ProjectTA = t2.ProjectTA
            and t1.TID = t2.TID
            and t1.Sites = t2.Sites
            and t1.name = t2.name
          FOR XML PATH (''))
          , 1, 1, '')  AS inits,
  t1.name
from yt t1;

参见SQL Fiddle with demo

或者你可以使用CROSS APPLY和FOR XML PATH:

select distinct t1.country,
  t1.ProjectTA, 
  t1.Complexity,
  t1.TID,
  t1.Sites, 
  left(t2.inits, len(t2.inits)-1) inits,
  t1.name
from yt t1
cross apply
(
  select t2.Inits + ', '
  from yt t2
  where t1.Country = t2.Country
    and t1.ProjectTA = t2.ProjectTA
    and t1.TID = t2.TID
    and t1.Sites = t2.Sites
    and t1.name = t2.name
  FOR XML PATH('')
) t2 (inits);

参见SQL Fiddle with Demo.这些都产生了结果:

See SQL Fiddle with Demo. These both yield the result:

|       COUNTRY | PROJECTTA |  COMPLEXITY |  TID | SITES |      INITS |              NAME |
-------------------------------------------------------------------------------------------
| United States |     A8022 | Obesity Low | 4692 |    69 |       hale | ePublishing Group |
| United States |     A8022 | Obesity Low | 4692 |    69 | jpni, jpni |        CBM Budget |
| United States |     A8022 | Obesity Low | 4692 |    69 |   JT, PIHR |                AD |
| United States |     S8033 |     CNS Low | 5423 |    69 | dedu, AHrp | ePublishing Group |
| United States |     S8033 |  CNS Medium | 5423 |    69 | dedu, AHrp | ePublishing Group |
| United States |     S8033 |  CNS Medium | 5423 |    69 |       ShyP |       CBM Payment |

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