testing for an author which does not exist

queries_original.py

import sqlite3


def get_cursor():
    conn = sqlite3.connect("library.db")
    return conn.cursor()


def select_all_records_by_author(cur, author):
    sql = "SELECT * FROM books WHERE author=?"
    cur.execute(sql, [author])
    """
    # adding check for no rows returned:
    print(f"cur.rowcount = {cur.rowcount}")
    if cur.rowcount < 1:
        print(f"No books by author {author}.")
        return
        """
    print(cur.fetchall())  # or use fetchone()
    print("\nHere is a listing of the rows in the table\n")
    for row in cur.execute("SELECT rowid, * FROM books ORDER BY author"):
        print(row)


def select_using_like(cur, text):
    print("\nLIKE query results:\n")
    sql = f"""
    SELECT * FROM books
    WHERE title LIKE '{text}%'"""
    cur.execute(sql)
    print(cur.fetchall())


if __name__ == '__main__':
    cursor = get_cursor()
    select_all_records_by_author(cursor, author='Mike Driscoll')
    # testing for an author which does not exist:
    select_all_records_by_author(cursor, author='Ryan Sherwood')
    select_using_like(cursor, text='Python')

Output:

C:\Users\ryan-\PycharmProjects\TADA\venv\Scripts\python.exe C:/Users/ryan-/PycharmProjects/TADA/queries_original.py
[('Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub'), ('Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')]

Here is a listing of the rows in the table

(3, 'Automate the Boring Stuff with Python', 'Al Sweigart', '', 'No Starch Press', 'PDF')
(4, 'The Well-Grounded Python Developer', 'Doug Farrell', '2020', 'Manning', 'Kindle')
(1, 'Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub')
(2, 'Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')

LIKE query results:

[('Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub'), ('Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')]

Process finished with exit code 0

Rev 2 output:

I'm not in the database so it shouldn't list Mike's books!

C:\Users\ryan-\PycharmProjects\TADA\venv\Scripts\python.exe C:/Users/ryan-/PycharmProjects/TADA/queries_original.py
[('Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub'), ('Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')]

Here is a listing of the rows in the table

(3, 'Automate the Boring Stuff with Python', 'Al Sweigart', '', 'No Starch Press', 'PDF')
(4, 'The Well-Grounded Python Developer', 'Doug Farrell', '2020', 'Manning', 'Kindle')
(1, 'Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub')
(2, 'Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')
[]

Here is a listing of the rows in the table

(3, 'Automate the Boring Stuff with Python', 'Al Sweigart', '', 'No Starch Press', 'PDF')
(4, 'The Well-Grounded Python Developer', 'Doug Farrell', '2020', 'Manning', 'Kindle')
(1, 'Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub')
(2, 'Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')

LIKE query results:

[('Python 101', 'Mike Driscoll', '09/01/2020', 'Mouse vs. Python', 'epub'), ('Python Interviews', 'Mike Driscoll', '02/01/2018', 'Packt Publishing', 'softcover')]

Process finished with exit code 0