字符串当量的总和连接

Question

我想要一个查询输出1行左侧表中的Id和来自连接表的描述。

架构：

person 
---------  
id (int) 

role 
------------- 
id (int) 
description (varchar(100)) 

personrole 
------------- 
personid (int) 
roleid (int) 

实施例的数据：

person 
------------ 
id 
1 
2 

role 
------------ 
id description 
1 user 
2 admininstrator 
3 tester 

personrole 
------------- 
personid roleid 
1   1 
2   1 
2   2 
2   3 

所以，希望我的输出为：

PersonId Roles 
1   user 
2   user;administrator;tester 

Answer 1

SELECT 
    p.ID PersonID, 
    STUFF(
     (SELECT ';' + b.description 
      FROM personrole a 
       INNER JOIN role b 
        ON a.roleid = b.id 
      WHERE a.personid = p.id 
      FOR XML PATH ('')) 
      , 1, 1, '') AS DescriptionList 
FROM person AS p 
GROUP BY p.ID 

• SQLFiddle Demo

OUTPUT

╔══════════╦════════════════════════════╗ 
║ PERSONID ║  DESCRIPTIONLIST  ║ 
╠══════════╬════════════════════════════╣ 
║  1 ║ user      ║ 
║  2 ║ user;admininstrator;tester ║ 
╚══════════╩════════════════════════════╝ 

Answer 2

一个其他SQL例如：使用GROUP_CONCAT上单个表组的一个小镇的每个名字的客户端。

脚本SQLite的：

表：

CREATE TABLE IF NOT EXISTS 'user'(
     prenom STRING, 
     age INTEGER, 
     ville STRING); 

数据：

INSERT INTO 'user' ('prenom', 'age', 'ville') VALUES 
     ('Anthony', 20, 'Toulouse'), 
     ('Clarisse', 18, 'Paris'), 
     ('Madeleine', 58, 'Paris'), 
     ('Jacques', 45, 'Toulouse'), 
     ('Henry', 26, 'Toulouse'), 
     ('Lili', 14, 'Nice'), 
     ('Victoire', 38, 'Paris'); 

正常选择：

SELECT * FROM 'user'; 

OUTPUT：

prenom age ville 

-------- -- --------- 
Anthony 20 Toulouse 
Clarisse 18 Paris 
Madeleine 58 Paris 
Jacques 45 Toulouse 
Henry  26 Toulouse 
Lili  14 Nice 
Victoire 38 Paris 

所有prenom组由威乐：

SELECT ville, GROUP_CONCAT(prenom, ',') FROM user GROUP BY ville;

OUTPUT：

ville  liste 
-------- --------- 
Nice  Lili 
Paris  Clarisse,Madeleine,Victoire 
Toulouse Anthony,Jacques,Henry