如何以1到n的关系检索左表的一些随机行以及右表的所有相关行

Question

I have Two tables . One is Question with following properties:

1. QuestionId
2. Question_Description
3. Weight
4. NoofOption

and other is Answer with:

1. Id
2. QuestionId
3. IsCorrect

Note: Question and Answer have 1 to n relation

Now I need to select 10 random questions from question table and get all the rows of answers using join. I am new to sub query. :(

Answer 1

A subquery is definitely the way to go:

SELECT
    q.questionID, 
    q.question_Description,
    q.weight,
    q.NoOfOption
FROM
    (SELECT QuestionID, Question_Description, Weight, NoOfOption FROM Question ORDER BY RAND() LIMIT 0,10) as q
    LEFT OUTER JOIN Answers a 
        ON q.questionid = a.questionid

The subquery here just grabs 10 random questions. Then we LEFT OUTER JOIN that over to Answers.