Querying the table
Now that you have a grasp of what's happening in the datacamp_application
database, let's go ahead and write up a query for that database.
The goal is to get a feeling for the data in this exercise. You'll get the rating data for three sample users and then use a predefined helper function, print_user_comparison()
, to compare the sets of course ids these users rated.
This exercise is part of the course
Introduction to Data Engineering
Exercise instructions
- Complete the connection URI. The database is called
datacamp_application
. The host islocalhost
with port5432
. The username isrepl
and the password ispassword
. - Select the ratings of users with id:
4387
,18163
and8770
. - Fill in
print_user_comparison()
with the three users you selected.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Complete the connection URI
connection_uri = "postgresql://____:____@____:____/datacamp_application"
db_engine = sqlalchemy.create_engine(connection_uri)
# Get user with id 4387
user1 = pd.read_sql("SELECT * FROM rating ____ ____=____", db_engine)
# Get user with id 18163
user2 = pd.read_sql("SELECT * FROM rating ____ ____=____", db_engine)
# Get user with id 8770
user3 = pd.read_sql("SELECT * FROM rating ____ ____=____", db_engine)
# Use the helper function to compare the 3 users
print_user_comparison(____, ____, ____)