Mysql 在子查询中获取值

我不希望r.reguser\u id作为结果中的test列，如果我从Select语句中删除此列，则我在中遇到问题，其中bu.business\u id=r.reguser\u id并得到一个错误，返回的行数超过1行。

SELECT r.reguser_name ,  r.reguser_id as test,

(Select r.reguser_id as c, GROUP_CONCAT(i.industry_name) as Industry

From reguser r inner JOIN business_industry bu ON r.reguser_id = bu.business_id  join industry i ON bu.industry_id = i.industry_id

WHERE  bu.business_id = test

GROUP BY bu.business_id
) as indus

FROM reguser r

请告诉我如何解决这个问题？ 多谢各位

SELECT r.reguser_name ,  r.reguser_id,

(Select r1.reguser_id as c, GROUP_CONCAT(i.industry_name) as Industry

From reguser r1 inner JOIN business_industry bu ON r1.reguser_id = bu.business_id  join industry i ON bu.industry_id = i.industry_id

WHERE  bu.business_id = r.reguser_id

GROUP BY bu.business_id
) as indus

FROM reguser r

不要对主表和子查询中的表使用相同的alliase。这真是糟糕的做法

SELECT t1.user_name FROM
(SELECT r.reguser_name as user_name,  r.reguser_id as test,

(Select r.reguser_id as c, GROUP_CONCAT(i.industry_name) as Industry

From reguser r inner JOIN business_industry bu ON r.reguser_id = bu.business_id  join     industry i ON bu.industry_id = i.industry_id

WHERE  bu.business_id = test

GROUP BY bu.business_id
) as indus

FROM reguser r)t1
WHERE t1.user_name IS NOT NULL

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我认为，如果以这种方式进行查询时使用SQLDeveloper，则需要使用某种where子句，即为select查询提供别名。希望这有帮助。

是的，将r改为r1解决了我的问题，非常感谢。