MYSQL：连接两个表并使用一个随机列

Question

I'm rather new to mySql and I can't seem to get my head around a problem I have. What I want to do is to use a table (LessonPlans) and join it with a random image from another table (Images), but only if that image is marked with the same language as the LessonPlans. The images should continue adding only as long as there are more input from LessonPlans.

In detail:

I need to show Name , Level and Aim from LessonPlans together with a random image ( Name-img ) from Images , but only when both LessonPlans and Images have Language (for example English) in common. This should be continued as long as there are rows in LessonPlans , even if that means repeating Images .

I have tried all sorts of solutions from differnet sources, but I either get everything random, or everything repeated.

ps. I'm new to Stackoverflow so excuse me if I didn't make myself very clear

//Edit

This is the tables:

LessonPlans Id Subject Language Level Aim

Images Id Name-img Language

/Håkan

Answer 1

SELECT LessonPlans.Name , LessonPlans.Level , LessonPlans.Aim , LessonPlans.language ,
       Images.img, Images.language 
FROM   LessonPlans , Images
ON  LessonPlans.commonfield=Images.commonfield
WHERE   LessonPlans.language      = 'English';

Answer 2

Try this -->>

SELECT LessonPlans.Subject , LessonPlans.Level , LessonPlans.Aim , LessonPlans.language ,
       Images.Name_img
FROM   LessonPlans INNER JOIN Images
ON  LessonPlans.language=Images.language

Answer 3

SELECT * FROM
    (SELECT l.Id, l.Subject, l.Language, i.`Name-img` 
        FROM LessonPlans l, Images i
        WHERE l.Language = i.Language
        ORDER BY RAND()
    ) a
GROUP BY a.Subject
ORDER BY a.Id

You can use all fields you need. Please check this example at the SQLFiddle . Sometimes image names may repeat because there are few images in the sample schema.

UPD 1: Add specific language

SELECT * FROM
    (SELECT l.Id, l.Subject, l.Language, i.`Name-img` 
        FROM LessonPlans l
        JOIN Images i
        ON l.Language = i.Language
        WHERE l.Language = 'en'
        ORDER BY RAND()
    ) a
GROUP BY a.Subject
ORDER BY a.Id

Try this at the SQLFiddle