mysql：复制表中的某些行，更改重复的信息

I've been working around this post, but I can not arrive to a suitable solution for what I have to do, which it is next: I have this equivalences:

subject1 = subjectA
subject2 = subjectB
subject3 = subjectC

then I have a csv file with next data:

hour,subject,teacher,room
10-11,subject1,teacher1,room1
11-12,subject2,teacher2,room1
09-11,subject3,teacher3,room2
10-11,subject4,teacher2,room3

then I export this csv to mysql, so what I need to do is

duplicate row where subject like "subject1" and replace "subject1" by "subjectA";

and the same for subject2, subject3, when I say replace, I mean the text string "subject1" by the text string "subjectA".

I hope I could make myself clear, thanks a lot.

As I couldn't manage to make it the mysql way I did it the shell-script way, I upload the csv file through a web interface where there is a script behind the scene that send it to the mysql, so I did a preprocess that modify the csv file and then send it to the mysql-server, so this is the line(s) I added at the begining of the file:

<?php
$file=$_POST['file'];

system("sed -i -r 's/^(.*)(Original Subject)(.*)$/\\1\\2\\3\
\\1New Subject\\3/g' $file");

.....

So I substitute the original line by 2 lines, the original one plus the new one...

Simply select the columns where data doesn't change (hour, teacher, etc.) and the string you want to replace where data does change (subjectA). Note that "subjectA" is surrounded by quotes.

INSERT INTO 
    `your_table` 
    (`hour`, `subject`, `teacher`, `room`) 
        SELECT 
            `hour`, 'subjectA', `teacher`, `room` 
        FROM 
            `your_table` 
        WHERE 
            `subject` = 'subject1'