mysql：复制表中的某些行，更改重复的信息

Question

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.

Answer 1

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...