如何显示发布到我的论坛中的答案数量? [英] How to show the numbers of answers posted into my forum?

问题描述

我正在使用Java技术建立一个论坛.实际上，它几乎快要完成了，但是问题是我想在论坛中显示答案的数量.好吧，让我们深入了解.

i'm making a forum using Java technologies. Actually it is almost near to complete but the problem is I want to show numbers of answer into my forum. Okay let's understand in deeply.

首先，我创建了一个名为index.jsp的文件，在这里我们可以看到所有问题.对于e.g，请访问stackoverflow.com，我们在一个问题中也看到了所有问题numbers of answers posted.这就是我想显示在index.jsp中的全部内容.

Firstly, i've created a file named as index.jsp where we could see all questions. For e.g Have a look into stackoverflow.com we see all question as well numbers of answers posted in one question. That's all i wanted to show into my index.jsp.

我正在使用select * from question_table..提取所有问题.实际上是进入我的view question文件.我正在使用在answer's table中创建的question_id表来获取答案.您非常清楚要显示答案，特别是我们需要将相同的question_id保存到答案的表以及问题的表中.

I'm fetching all questions using select * from question_table... Actually into my view question file. I'm fetching the answer using question_id table which is created into answer's table. You know very well to show answer in particular we need to save the same question_id into answer's table as well question's table.

对于e.g:

看看这张桌子，我设计了同样的东西:

look at this table i designed the same thing:

create table if not exists thread_question(
question_id INT NOT NULL auto_increment,
question_title VARCHAR(500) NOT NULL,
question VARCHAR(100000) NOT NULL,
question_dateTime VARCHAR(100) NOT NULL,
PRIMARY KEY(question_id)
);

create table if not exists thread_answer(
answer_id INT NOT NULL auto_increment,
question_id INT NOT NULL references thread_question(question_id),
answer VARCHAR(100000) NOT NULL,
answer_dateTime VARCHAR(100) NOT NULL,
PRIMARY KEY(answer_id)
); 

就像您在这里看到的一样，question_id被保存到两个表中.我在这里使用相同的过程.

As well you could see here, question_id is saved into two tables. Same process i'm using here.

现在我想在我的主页上显示我的答案数量.任何的想法?在这里可以使用什么.我真的被困在这里.请帮忙！

Now i want to show my number of answers into my main page. Any idea? what can be used here. I really stuck here. Please help!

当然可以，谢谢您的帮助！

Surely, Help would be appreciated!!

已

EDITED:

这是我的完整表格代码:

Here is my full codes of table:

create table if not exists thread_question(
question_id INT NOT NULL auto_increment,
first_name VARCHAR(100) NOT NULL,
last_name VARCHAR(100) NOT NULL,
question_title VARCHAR(500) NOT NULL,
question VARCHAR(100000) NOT NULL,
question_dateTime VARCHAR(100) NOT NULL,
PRIMARY KEY(question_id)
);

create table if not exists thread_answer(
answer_id INT NOT NULL auto_increment,
question_id INT NOT NULL references thread_question(question_id),
first_name VARCHAR(100) NOT NULL,
last_name VARCHAR(100) NOT NULL,
answer VARCHAR(100000) NOT NULL,
answer_dateTime VARCHAR(100) NOT NULL,
PRIMARY KEY(answer_id)
);

这里是 SCREENSHOT .

请帮助！！

推荐答案

使用内部联接获取每个问题的答案数量

use inner join to fetch number of answer per question

   SELECT thread_question.question_id, COALESCE(sub.counts,0) AS NumerOfAnswer 
   FROM thread_question LEFT JOIN (
        SELECT question_id, COUNT(answer_id) AS counts
        FROM thread_answer
        GROUP BY question_id
    ) sub ON thread_question.question_id = sub.question_id
  ORDER BY NumerOfAnswer

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