v Select From Multiple Tables Simultaneously - SQL

Select From Multiple Tables Simultaneously

Note: This tutorial was written using Catherine Devlin's SQL in Jupyter Notebooks library. If you have not using a Jupyter Notebook, you can ignore the two lines of code below and any line containing %%sql. Furthermore, this tutorial uses SQLite's flavor of SQL, your version might have some differences in syntax.

For more, check out Learning SQL by Alan Beaulieu.

# Ignore
%load_ext sql
%sql sqlite://
%config SqlMagic.feedback = False

Create Two Tables, Criminals And Crimes

%%sql

-- Create a table of criminals
CREATE TABLE criminals (pid, name, age, sex, city, minor);
INSERT INTO criminals VALUES (412, 'James Smith', 15, 'M', 'Santa Rosa', 1);
INSERT INTO criminals VALUES (234, 'Bill James', 22, 'M', 'Santa Rosa', 0);
INSERT INTO criminals VALUES (632, 'Stacy Miller', 23, 'F', 'Santa Rosa', 0);
INSERT INTO criminals VALUES (621, 'Betty Bob', NULL, 'F', 'Petaluma', 1);
INSERT INTO criminals VALUES (162, 'Jaden Ado', 49, 'M', NULL, 0);
INSERT INTO criminals VALUES (901, 'Gordon Ado', 32, 'F', 'Santa Rosa', 0);
INSERT INTO criminals VALUES (512, 'Bill Byson', 21, 'M', 'Santa Rosa', 0);
INSERT INTO criminals VALUES (411, 'Bob Iton', NULL, 'M', 'San Francisco', 0);

-- Create a table of crimes
CREATE TABLE crimes (cid, crime, city, pid_arrested, cash_stolen);
INSERT INTO crimes VALUES (1, 'fraud', 'Santa Rosa', 412, 40000);
INSERT INTO crimes VALUES (2, 'burglary', 'Petaluma', 234, 2000);
INSERT INTO crimes VALUES (3, 'burglary', 'Santa Rosa', 632, 2000);
INSERT INTO crimes VALUES (4, NULL, NULL, 621, 3500); 
INSERT INTO crimes VALUES (5, 'burglary', 'Santa Rosa', 162, 1000); 
INSERT INTO crimes VALUES (6, NULL, 'Petaluma', 901, 50000); 
INSERT INTO crimes VALUES (7, 'fraud', 'San Francisco', 412, 60000); 
INSERT INTO crimes VALUES (8, 'burglary', 'Santa Rosa', 512, 7000); 
INSERT INTO crimes VALUES (9, 'burglary', 'San Francisco', 411, 3000); 
INSERT INTO crimes VALUES (10, 'robbery', 'Santa Rosa', 632, 2500); 
INSERT INTO crimes VALUES (11, 'robbery', 'Santa Rosa', 512, 3000);
[]

View All Unique City Names From Both Tables

%%sql

-- Select city name
SELECT city 

-- From criminals table
FROM criminals

-- Then combine with
UNION

-- Select city names
SELECT city 

-- From crimes table
FROM crimes;
city
None
Petaluma
San Francisco
Santa Rosa

View All City Names From Both Tables

%%sql

-- Select city name
SELECT city 

-- From criminals table
FROM criminals

-- Then combine with
UNION ALL

-- Select city names
SELECT city 

-- From crimes table
FROM crimes;
city
Santa Rosa
Santa Rosa
Santa Rosa
Petaluma
None
Santa Rosa
Santa Rosa
San Francisco
Santa Rosa
Petaluma
Santa Rosa
None
Santa Rosa
Petaluma
San Francisco
Santa Rosa
San Francisco
Santa Rosa
Santa Rosa