Finding duplicate values in a SQL table

The following example uses ipython-sql. To install:pip install ipython-sql

%sql is a Jupyter magic command and can be ignored when not using Jupyter notebooks.

Configure SQL for Jupyter notebook

#Load sql
%load_ext sql
#connect to sqlite
%sql sqlite://

Create a table

%%sql
CREATE TABLE players (first_name, last_name, age);

%%sql
INSERT INTO players (first_name, last_name, age) VALUES 
    ('Lebron', 'James', 33),
    ('Steph', 'Curry', 30),
    ('Mike', 'Jordan', 55),
    ('Mike', 'Bibby', 40);

Count the # of unique first names in the table

%%sql 
--Select the distinct # of first names in our table, players
SELECT COUNT(DISTINCT(first_name)) FROM players

COUNT(DISTINCT(first_name))
3