Here are a few examples of how to:

  • run SQL queries to retrieve information from a database and
  • apply AND, OR, and NOT operators to filter SQL queries.

Find unsuccessful login attempts that happened after 1800:

SELECT *
FROM log_in_attempts
WHERE login_time > '18:00:00' AND success = 0;

Now check for any failed login attempts that happened on two days:

SELECT *
FROM log_in_attempts
WHERE login_date = '2022-05-09' OR login_date = '2022-05-08';

Now check for any failed login attempts that happened outside of a country, e.g. Mexico:

SELECT *
FROM log_in_attempts
WHERE NOT country LIKE 'MEX%';

To see the columns and values in the employees table:

SELECT *
FROM employees;

Get employee_id that work in Marketing and work in the East building:

SELECT *
    -> FROM employees
    -> WHERE department = 'Marketing' AND office LIKE 'East%';

Next grab employee id’s from Finance and Sales:

SELECT *
FROM employees
WHERE department = 'Finance' OR department = 'Sales';

Finally, list everyone who doesn’t work in the IT department:

SELECT *
FROM employees
WHERE NOT department = 'Information Technology';