Question

我在民意调查脚本中工作，我有两个表{hs_questions_q} {hs_answers_ans}，第一个存储了问题，第二个存储了答案

我使用这个sql语句来检索数据

SELECT * FROM hs_questions_q INNER JOIN hs_answers_ans ON id_q=idq_ans WHERE active_q ='1' and home_q ='1' ORDER BY id_q DESC limit 1

我很奇怪，我无法在我的PHP代码中处理这个查询如何仅从问题表和答案表返回最后一行，但我需要从问题表中检索最后一行并且与答案表相关的所有行

Answer 1

这将在表中的每个问题返回1行而不是答案的num行：

我假设结构：

hs_questions_q (id,desc)

hs_answers_ans(id,desc)

SELECT question.desc, group_concat(hs_answers_ans.desc SEPARATOR '#')
FROM (select * 
          from hs_questions_q 
          where active_q ='1' and home_q ='1' ORDER BY id_q DESC limit 1) question
INNER JOIN hs_answers_ans ON id_q=idq_ans
group by question.id

result:
question1 | Answer1#Answer2#Answer3

稍后，您可以将其拆分为＆＃39;＃＆＃39;在php端检索结果后。

如果超过允许的数据包大小，您可能会收到截断的答案。你可以通过

解决它

SET SESSION group_concat_max_len = 6000(any threshold);

Answer 2

我认为这大致是你正在寻找的东西：

SELECT * FROM 
         (select * 
          from hs_questions_q 
          where active_q ='1' and home_q ='1' ORDER BY id_q DESC limit 1) question
 INNER JOIN hs_answers_ans ON id_q=idq_ans

我不知道active_q和home_q是否属于问题表或答案

Answer 3

这是因为你试图抓住一行并加入多行不同的数据...我不认为这会有效。

我会选择问题，然后使用问题中的ID分别获取所有答案。

Answer 4

select * from hs_answer_ans where idq_ans in (select id_q from hs_questions_q where active_q ='1' and home_q ='1' ORDER BY id_q DESC limit 1)

抱歉，评论中有一些错字...... :)

Answer 5

此查询应该为您提供所需的结果：

SELECT * 
FROM `hs_questions_q` 
INNER JOIN `hs_answers_ans` ON `id_q` = `idq_ans` 
WHERE `idq_ans` = (
    SELECT MAX(`id_q`)
    FROM `hs_questions_q`
    WHERE `active_q` ='1'
    AND `home_q` ='1'
    );

希望它有所帮助！

SELECT sql语句，用于从表中检索一行，从其他表中检索许多相关行

5 个答案: