将关联值从一个表存储到mysql中的另一个表

Question

Table one

Id       subject       class     teacher
1        English         1          1
2        Math            1          2
3        SST             1          3
4        Computer        1          1
5        Physics         1          3
6        Chemistry       1          3

Each subject assigned to particular teacher, some subject has same teacher.

Now i want to store values in another table having these fields and other fields as well.
Table Two

id       subject        teacher

Whereas form only post subject ids, how can i get teacher id against each subject id from Table one and store it in table two?

Answer 1

Your question is very unclear. Are you asking for how to use relational databases and foreign keys? If so I would read up on how a relational database works and that will answer your question. If the question is about how to do this in code then please state that and also post your attempt at it.

What i think you want to do is get the of the subject posted, ie query the database :

SELECT subject, teacher FROM table_one WHERE id = 'POSTED_ID'  

Then insert the new record into the table two, something like :

INSERT INTO table_two (subject, teacher) VALUES ('subject_value', 'teacher_value')   

Hope this helps!