MySQL使用JOIN和GROUP_CONCAT

Question

努力让这个查询有效：

$query_search = "SELECT questionnaires_index.id, questionnaires_index.ea_num, questionnaires_index.address, questionnaires_index.status, questionnaires_index.json_stored users.username FROM questionnaires_index INNER JOIN users ON questionnaires_index.interviewer_id = users.id WHERE questionnaires_index.interviewer_id IN (SELECT GROUP_CONCAT(id) FROM users WHERE supervisor = (SELECT id FROM users WHERE username = '".$username."'))";

出现此错误：

  

查询错误：。您的SQL语法有错误;检查   手册，对应右边的MySQL服务器版本   在'.username FROM questionnaires_index INNER JOIN附近使用的语法   用户ON users.id =问卷'在第1行

查询一直有效，直到我将users.username添加到带有JOIN语句的结果集。请帮忙。

Answer 1

你错过了一个逗号

$ query_search =“SELECT questionnaires_index.id，questionnaires_index.ea_num，questionnaires_index.address，questionnaires_index.status，questionnaires_index.json_stored，users.username FROM questionnaires_index INNER JOIN users ON questionnaires_index.interviewer_id = users.id WHERE questionnaires_index.interviewer_id IN（ SELECT GROUP_CONCAT（id）FROM users WHERE supervisor =（SELECT id FROM users WHERE username ='“。$ username。”'））“;

Answer 2

你似乎忘了在questionnaires_index.json_stored和users.username之间加一个逗号。

$query_search = "SELECT questionnaires_index.id, questionnaires_index.ea_num, questionnaires_index.address, questionnaires_index.status, questionnaires_index.json_stored ,users.username FROM questionnaires_index INNER JOIN users ON questionnaires_index.interviewer_id = users.id WHERE questionnaires_index.interviewer_id IN (SELECT GROUP_CONCAT(id) FROM users WHERE supervisor = (SELECT id FROM users WHERE username = '".$username."'))