mysql - 如何将数据库行合并在一起？

Question

我在下面有一个查询，它显示了这些结果：

SELECT q.QuestionId, q.QuestionContent, an.Answer
FROM Answer an
INNER JOIN Question q ON q.AnswerId = an.AnswerId;

查询结果：

QuestionId     QuestionContent           Answer
1              Who are me and you         B
1              Who are me and you         D
2              Name these Cars            A
2              Name these Cars            B
2              Name these Cars            E
3              What is 2+2                B

我想要做的是将相同 QuestionId 的答案合并在一起，因此结果如下所示：

QuestionId     QuestionContent           Answer
1              Who are me and you         B D
2              Name these Cars            A B E
3              What is 2+2                B

这可能吗？

谢谢

Answer 1

试试这个 -

SELECT q.QuestionId,
       q.QuestionContent,
       GROUP_CONCAT(an.Answer, SEPARATOR ' ')
FROM Answer an
INNER JOIN Question q ON q.AnswerId = an.AnswerId
GROUP BY q.QuestionId,
       q.QuestionContent