Used for Filtering Data while Displaying / Reading
SELECT * FROM xyz
SELECT column_name FROM xyz
SELECT c1, c2 FROM xyz
-- Displays Column Name as id instead of cat_id
SELECT cat_id AS id FROM xyz
SELECT * FROM cats WHERE age = 4
-- Case insensitive by default
SELECT * FROM cats WHERE name = 'yg'
SELECT * FROM cats WHERE age = id
-- Returns Unique Records without repetition
SELECT DISTINCT author_lname FROM books