Missing Values

SQL: SELECT: Basics

SELECT * FROM <table> WHERE <column> IS NULL;

//To filter out missing values use can use IS NOT NULL:

SELECT * FROM <table> WHERE <column> IS NOT NULL;

Example:

SELECT * FROM people WHERE last_name IS NULL;
SELECT * FROM vhs_rentals WHERE returned_on IS NULL;
SELECT * FROM car_rentals WHERE returned_on IS NULL AND location = "PDX";

//OR

SELECT * FROM people WHERE email IS NOT NULL;
SELECT * FROM addresses WHERE zip_code IS NOT NULL;