Ordering in descending order by a single column
You can also use .order_by() to sort from highest to lowest by wrapping a column
in the desc() function. Although you haven't seen this function in action, it generalizes what you have already learned.
Pass desc() (for "descending") inside an .order_by() with the name of the column you want to sort by. For instance,
stmt.order_by(desc(table.columns.column_name)) sorts column_name in descending order.
This is a part of the course
“Introduction to Databases in Python”
Exercise instructions
- Import
descfrom thesqlalchemymodule. - Select all records of the
statecolumn from thecensustable. - Append an
.order_by()to sort the result output by thestatecolumn in descending order. Save the result asrev_stmt. - Execute
rev_stmtusingconnection.execute()and fetch all the results with.fetchall(). Save them asrev_results. - Print the first 10 rows of
rev_results.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Import desc
from ____ import ____
# Build a query to select the state column: stmt
stmt = ____
# Order stmt by state in descending order: rev_stmt
rev_stmt = stmt.order_by(____)
# Execute the query and store the results: rev_results
rev_results = ____
# Print the first 10 rev_results
print(____)
This exercise is part of the course
Introduction to Databases in Python
In this course, you'll learn the basics of relational databases and how to interact with them.
In this chapter, you will build on your database knowledge by writing more nuanced queries that allow you to filter, order, and count your data—all within the Pythonic framework provided by SQLAlchemy.
Exercise 1: Filtering and targeting dataExercise 2: Connecting to a PostgreSQL databaseExercise 3: Filter data selected from a Table - SimpleExercise 4: Filter data selected from a Table - ExpressionsExercise 5: Filter data selected from a Table - AdvancedExercise 6: Ordering query resultsExercise 7: Ordering by a single columnExercise 8: Ordering in descending order by a single columnExercise 9: Ordering by multiple columnsExercise 10: Counting, summing, and grouping dataExercise 11: Counting distinct dataExercise 12: Count of records by stateExercise 13: Determining the population sum by stateExercise 14: SQLAlchemy and pandas for visualizationExercise 15: ResultsSets and pandas DataFramesExercise 16: From SQLAlchemy results to a plotWhat is DataCamp?
Learn the data skills you need online at your own pace—from non-coding essentials to data science and machine learning.