Dat Le lenguyenthedat

	-- Bad use of aggregation
	SELECT
	users.id,
	users.email,
	users.name,
	MAX(users.created_at) AS created_at, -- not necessary
	COUNT(orders.id) AS orders_count
	FROM orders
	LEFT JOIN users
	ON users.id = orders.user_id

	-- Bad: multiple type of joins unecessarily used, start from `orders` as base table is not ideal
	SELECT
	DATE(orders.created_at) AS date,
	users.email
	FROM orders
	LEFT JOIN users
	ON users.id = orders.user_id
	JOIN order_items
	ON order_items.order_id = orders.id
	GROUP BY 1, 2

	-- Bad: no capitalization
	select
	products.id,
	case
	when products.sold_by = 0 then 'item'
	when products.sold_by = 1 then 'weight'
	when products.sold_by = 2 then 'volume'
	end as sold_by,
	product_categories.category_name
	from products

	import System.Environment (getArgs)
	import System.Random (StdGen, newStdGen, random)
	import Data.Bits (popCount)
	import Data.List (unfoldr)
	import Data.Int (Int16)

	main = do
	seed <- newStdGen
	args <- getArgs
	let size = read $ head args

	"continent_code", "country_code","continent_name","country_name","country_iso3","country_number","country_full_name
	"AS","AF","Asia","Afghanistan","AFG","004","Islamic Republic of Afghanistan"
	"EU","AX","Europe","Åland Islands","ALA","248","Åland Islands"
	"EU","AL","Europe","Albania","ALB","008","Republic of Albania"
	"AF","DZ","Africa","Algeria","DZA","012","People"s Democratic Republic of Algeria"
	"OC","AS","Oceania","American Samoa","ASM","016","American Samoa"
	"EU","AD","Europe","Andorra","AND","020","Principality of Andorra"
	"AF","AO","Africa","Angola","AGO","024","Republic of Angola"
	"NA","AI","North America","Anguilla","AIA","660","Anguilla"
	"AN","AQ","Antarctica","Antarctica","ATA","010","Antarctica the territory South of 60 deg S"