我可以按另一个表中的记录数对SQL查询结果进行排序吗？

Question

这样的事情：

SELECT count(Answers.ID) as answertotal, Questions.* 
FROM Questions 
LEFT JOIN Answers ON Answers.qid=Questions.ID 
ORDER BY answertotal

我正在使用SQLite，但任何示例都应该有所帮助。

Answer 1

在MySQL中，这可行：

SELECT count(Answers.ID) as answertotal, Questions.* 
FROM Questions 
LEFT JOIN Answers ON Answers.qid=Questions.ID 
GROUP BY Questions.ID
ORDER BY answertotal

在SQLite中，您可能需要添加一个额外的图层：

SELECT q.*, tots.answertotal
FROM Questions q
INNER JOIN ( 
  SELECT count(Answers.ID) as answertotal, Questions.ID as questionid
  FROM Questions 
  LEFT JOIN Answers ON Answers.qid=Questions.ID 
  GROUP BY Questions.ID
) tots ON tots.questionid = q.ID
ORDER BY tots.answertotal