将多个表中的数据获取到单行中，同时连接一些值

我正在尝试从表中检索数据并将多行合并为一列，而不重复任何信息。

我有以下表格：简介、资格、项目。

Profile

pro_id  surname       firstname   
------  -------       ----------
   1    John          James           
   2    King          Fred        
   3    Luxury-Yachts Raymond

Qualification

pro_id  Degree   School               Year
------  ------   ------               -----
   1    MBA      Wharton university   2002        
   1    LLB      Yale University      2001    
   2    BSc      Covington University 1998
   2    BEd      Kellog University    1995

Projects

pro_id  Title                         Year
------  ------                        ------   
   1    Social Networking             2003        
   1    Excavation of aquatic debris  2007    
   2    Design of solar radios        1992
   2    Development of expert systems 2011
  

我想检索每个人的所有信息，每个人在结果中只出现一次。有关资格和项目的信息应分别位于各自的列中（一列用于资格，另一列用于项目），并以逗号分隔。例如，上述样本数据的结果应为：

1  John James             MBA Wharton university 2002, LLB Yale University 2001                     Social Networking 2003, Excavation of aquatic debris 2007, Design of Solar panels 2008
2  King Fred              BSc Covington University 1998, BEd Kellog University 1995, Msc MIT 2011   Design of solar radios 1992, Development of expert systems 2011
3  Raymond Luxury-Yachts
  

目前，我有这样的疑问：

SELECT pro_id,
       surname,
       firstname,
       group_concat(degree,school,year) AS qual,
       concat(Title,year) AS work
FROM profile,
       LEFT JOIN qualification
           ON qualification.pro_id = profile.pro_id 
       JOIN projects
           ON projects.pro_id = profile.pro_id 
GROUP BY pro_id

对于示例数据，此查询结果为：

1  John James MBA  Wharton university 2002,  Social Networking 2003 
1  John James LLB  Yale University 2001, Excavation of aquatic debris 2007
1  John James MBA  Wharton university 2002,  Social Networking 2003, Excavation of aquatic debris 2007
etc
  

注意：Raymond Luxury-Yachts 未出现在当前结果中。

我不想要重复的结果记录。此外，如果姓氏在资格和项目表中没有任何条目，我希望查询返回姓名并在资格和项目表中显示一个空字段，而不是完全忽略它们。

将 LEFT JOIN 替换为 JOIN

Select pro_id, surname, firstname, group_concat(degree,school,year) as qual,concat(Title,year) as work 
from profile
join qualification on qualification.pro_id = profile.pro_id 
join projects on projects.pro_id = profile.pro_id group by pro_id

“内连接”和“外连接”有什么区别？ https://stackoverflow.com/questions/38549/sql-difference-between-inner-and-outer-join