the gem active record that allows you to write ruby and translates from ruby to sql.

Select *
is Recipe.all
when you do where is always a collection even if its just one

&discount=true


Recipe.count <<< alias for Recipe.length

Recipe.sum(:prep_time) <<< sum up prep time
Recipe.average(:prep_time)


find_by always returns a single instance

Recipe.all.order(:chef) <<< orders by chef
Recipe.all.order(chef: :desc) < order desc

Recipe

Select *
FROM recipes
WHERE chef = "Rachel Ray";

Recipe.where(chef: "Rachel Ray")

Rails c << irb
Recipe.all << to show all

use Recipe.where("chef=?", "Rachel Ray")


Recipe.where('title iLIKE ?', query) always use this method to  prevent sql injection attacks.
Do not use interpolation like Recipe.where('title iLIKe '#{query}'') never do this sql injections attacks very likely


Recipe where if you want a collection
Recipe.where(chef: "Josh")

Recipe find_by() if you want to find one
Recipe.find_by(chef: "Josh") <<< find by the first one or
Recipe.find(2) <<< 2 is the id


Query comands
SELECT title
FROM recipes;
SELECT title, chef, created_at
FROM recipes;


SELECT *
FROM recipes; <<< returns all info


WHERE chef = 'Josh';


only postgress uses single ''

SELECT AVG(prep_time)
FROM recipes;

SELECT AVG(prep_time)
FROM recipes;


SELECT SUM (prep_time)
FROM recipes;

SELECT *
FROM recipes
WHERE chef iLIKE '%Josh%';

iLIKE is case insensitive

SELECT *
FROM recipes
WHERE prep_time >= 60
ORDER BY prep_time DESC
LIMIT 1;
ORDER BY <<< does the order
LIMIT 1;
ORDER BY prep_time DESC(ASCD).