Como criar e usar exibições do MySQL

O que é uma visualização do MySQL?

Quais são as vantagens de usar visualizações?

Tabelas para este exercício

• Motoristas
• Faixas
• Corridas
• Termina    

create table drivers
(
  id int auto_increment,
  name varchar(64) not null,
  car_number int not null,
  constraint drivers_pk
     primary key (id)
);
create table tracks
(
  id int auto_increment,
  name varchar(64) not null,
  location varchar(64) not null,
  constraint track_pk
     primary key (id)
);
create table races
(
  id int auto_increment,
  name varchar(64) not null,
  track int not null,
  distance int not null,
  constraint races_pk
     primary key (id)
);


create table finishes
(
  id int auto_increment,
  driver int not null,
  race int not null,
  position int not null,
  constraint finishes_pk
     primary key (id)
);

Motoristas

• Buddy Baker 28
• Dale Earnhardt Jr. 8
• Ricky Rudd 88

insert into drivers (name,car_number) values
  ('Buddy Baker',28),
  ('Dale Earnhardt Jr.',8),
  ('Ricky Rudd',88);

Pistas de corrida

• Talladega Superspeedway - Lincoln, AL
• Daytona International Speedway - Daytona Beach, Flórida
• Autódromo de Indianápolis - Autódromo, IN
• Michigan International Speedway - Brooklyn, MI

insert into tracks (name,location) values
  ('Talladega Superspeedway','Lincoln, AL'),
  ('Daytona International Speedway','Daytona Beach, FL'),
  ('Indianapolis Motor Speedway','Speedway, IN'),
  ('Michigan International Speedway','Brooklyn, MI');

Corridas

• Daytona 500,2.500
• Talladega 500.1.500
• Brickyard 400,3, 400
• Michigan 400,4,400

insert into races (name,track,distance) values
  ('Daytona 500',2,500),
  ('Talladega 500',1,500),
  ('Brickyard 400',3,400),
  ('Michigan 400',4,'400');

Resultados

• Ricky Rudd termina em primeiro
• Dale Earnhardt Jr termina em segundo 
• Buddy Baker termina em terceiro.

insert into finishes (driver, race, position) values
  (1,1,3),
  (2,1,2),
  (3,1,1);

Dados compilados

Primeira entrada de dados

select d.name as driver,
     r.name as race,
     t.name as track,
     t.location as location,
     f.position as position
  from finishes f
  left join races r
     on f.race = r.id
  left join tracks t
     on r.track = t.id
  left join drivers d
     on d.id = f.driver;

Segunda entrada de dados

insert into finishes (driver, race, position) values
  (1,2,2),
  (2,2,1),
  (3,2,3);

Criar visualização

create or replace view all_finishes as
select d.name as driver,
     r.name as race,
     t.name as track,
     t.location as location,
     f.position as position
  from finishes f
  left join races r
     on f.race = r.id
  left join tracks t
     on r.track = t.id
  left join drivers d
     on d.id = f.driver;

select * from all_finishes;

select * from all_finishes where position = 1;

select avg(position) as finish,
  driver
from all_finishes
  group by driver
     order by finish;

create view standings_leader as
select avg(position) as finish,
  driver
from all_finishes
  group by driver
     order by finish;

create view race_winners as
select * from all_finishes where position = 1;

Adicionando dados

insert into finishes (driver, race, position) values
  (1,3,1),
  (2,3,3),
  (3,3,2);

insert into finishes (driver, race, position) values
  (1,4,1),
  (2,4,2),
  (3,4,3);

select * from all_finishes;\

select * from race_winners;

select * from standings_leader;

Conclusão

Avalie-nos!