MySql 查询返回我不想要的结果

Question

我有一个如下的用户表:

      id                      some attribute
1196670907478919031,fb39f78853bfe42279a8f56bc5671eb9,.....
4915018864030990478,44ecf841a778525b925023321761e458, ........
3161434036923224050,2fd54178a92a4b1a83643d9faa1fec9e,......

现在我的friendedges表如下

      a                          b               status
 '4915018864030990478', '3161434036923224050', 'accepted'
 '4915018864030990478', '1196670907478919031', 'accepted'

为了获取 id=4915018864030990478 用户的所有 friend ，我编写了以下查询，但得到了以下结果 查询

select id, firstName, lastName, gender, pictureSet  FROM  Member m JOIN  friendedges f ON f.a = m.id where a = "4915018864030990478";

结果

 '4915018864030990478', 'sdsds', 'dsd', 'M', '1'
 '4915018864030990478', 'sdsds', 'dsd', 'M', '1'

我必须在哪里获取 friend ID。我不知道为什么它会产生重复的结果。

Answer 1

使用DISTINCT删除重复项:

select DISTINCT f.b, firstName, lastName, gender, pictureSet  
FROM  Member m
JOIN  friendedges f ON f.a = m.id 
where f.a = "4915018864030990478";