library(RMySQL)
library(tidyverse)
yhendus<-dbConnect(dbDriver("MySQL"), user='mart', password='ajutine1234', host=
'localhost', dbname='mart' )

paring<-dbSendQuery(yhendus, "SELECT first_name, last_name, 
  YEAR(date_of_birth) AS synniaasta, MIN(production_year) AS esmafilmiaasta, 
    MIN(production_year)-YEAR(date_of_birth) AS esmavanus
 FROM efis_film_maker
  JOIN efis_people ON efis_film_maker.people_id=efis_people.id
  JOIN efis_film ON efis_film_maker.film_id=efis_film.id 
  WHERE YEAR(date_of_birth) IS NOT NULL AND
    length(production_year)=4 AND
    efis_film_maker.classificator_code='FILM_MAKER_DIRECTOR'
  GROUP BY efis_people.id")
andmed=fetch(paring, n=-1)
noored=andmed %>% filter(esmafilmiaasta>=1985)
vanad=andmed %>% filter(esmafilmiaasta<=1985)
t.test(noored$esmavanus, vanad$esmavanus, conf.level=0.8)
ggplot(noored, aes(esmavanus))+geom_histogram(color="green", bins=10)+
  geom_histogram(data=vanad, color="blue", bins=10)