Alter many files, all with same variable in them

[woocha]

I have 100's of files that access a field in a mySQL DataBase.  I had to change the field name and now I have to update 100's of files.  The files read:

$sql = 'SELECT user_id, username, user_colour, user_birthday FROM '

I need it to now read:

$sql = 'SELECT id, nick, user_colour, user_birthday FROM '

 

I know I could go through all files and execute a replace 'user_id' with 'id', but that would take forever.  Does anyone know a program to do this easier?