How to visualize mysql data in d3js using django?

Yes, you can do this using Django. All you need to do is to create a Django PyDev(python) application. In the settings.py file give the database as,

    DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql', 
        'NAME': 'myDB',  # your mysql database name    
        'USER': '123', # your mysql user for the database
        'PASSWORD': '123', # password for user
        'HOST': '127.0.0.1', 
        'PORT': '3306', 
        } 

In the function definition in views.py give mysql connection as,

    conn = MySQLdb.connect (host = "127.0.0.1",
                        user = "root", # mysql root
                        passwd = "root", # mysql root password
                        db = "myDB")

Using cursor retrieve the data from table and then convert into json,

cursor.execute ("select <column> from <table>")

rows=dictfetchall(cursor)


object_list = []
for row in rows:
    d = collections.defaultdict()
    d['name'] = row['name']       
    object_list.append(d)

j = json.dumps(object_list)
objects_file = 'path of json file to be created'
m = open(objects_file,'w')
print >> m,j    #to write to file
conn.close() 

def dictfetchall(cursor):
    "Returns all rows from a cursor as a dictionary"
    desc = cursor.description
    return [
        dict(zip([col[0] for col in desc], row))
        for row in cursor.fetchall()
    ]

Now you can use this json file to create any type of d3js.