Sql success ch04
Post on 03-Jul-2015
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SQL Success
Chapter 4 slides
Stéphane Faroult
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Constraints
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movieid title country year_released 1 Casablanca us 1942 2 Goodfellas us 1990 3 Bronenosets Potyomkin ru 1925 4 Blade Runner us 1982 5 Annie Hall us 1977 6 Ying hung boon sik hk 1986 7 Sholay in 1975 8 On The Waterfront us 1954 9 Lawrence Of Arabia gb 1962 10 The Third Man gb 1949 11 Ladri di biciclette it 1948
movies
country_code country_name continent ru Russia EUROPE us United States AMERICA in India ASIA gb United Kingdom EUROPE fr France EUROPE hk Hong Kong ASIA it Italy EUROPE ca Canada AMERICA au Australia OCEANIA
countries
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select title, country_name, year_released from movies join countries on country_code = country where country_code <> 'us'
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select title, country_name, year_released from movies join countries on country_code = country where country_code <> 'us'
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select title, country_name, year_released from movies join countries on country_code = country where country_code <> 'us'
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select title, country_name, year_released from movies join countries on country_code = country where country_code <> 'us'
join on
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countries ru Russia EUROPE us United States AMERICA in India ASIA gb United Kingdom EUROPE fr France EUROPE hk Hong Kong ASIA it Italy EUROPE ca Canada AMERICA au Australia OCEANIA
movies 1 Casablanca us 1942 2 Goodfellas us 1990 3 Bronenosets Potyomkin ru 1925 4 Blade Runner us 1982 5 Annie Hall us 1977 6 Ying hung boon sik hk 1986 7 Sholay in 1975 8 On The Waterfront us 1954 9 Lawrence Of Arabia gb 1962 10 The Third Man gb 1949 11 Ladri di biciclette it 1948
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movies
ru Russia EUROPE us United States AMERICA us United States AMERICA
us United States AMERICA
us United States AMERICA
us United States AMERICA
gb United Kingdom EUROPE gb United Kingdom EUROPE
in India ASIA
it Italy EUROPE
hk Hong Kong ASIA
1 Casablanca us 1942 2 Goodfellas us 1990 3 Bronenosets Potyomkin ru 1925 4 Blade Runner us 1982 5 Annie Hall us 1977 6 Ying hung boon sik hk 1986 7 Sholay in 1975 8 On The Waterfront us 1954 9 Lawrence Of Arabia gb 1962 10 The Third Man gb 1949 11 Ladri di biciclette it 1948
joined to countries
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movies joined to countries
gb United Kingdom EUROPE
ru Russia EUROPE us United States AMERICA us United States AMERICA
us United States AMERICA
us United States AMERICA
us United States AMERICA
gb United Kingdom EUROPE
in India ASIA
it Italy EUROPE
hk Hong Kong ASIA
1 Casablanca us 1942 2 Goodfellas us 1990 3 Bronenosets Potyomkin ru 1925 4 Blade Runner us 1982 5 Annie Hall us 1977 6 Ying hung boon sik hk 1986 7 Sholay in 1975 8 On The Waterfront us 1954 9 Lawrence Of Arabia gb 1962 10 The Third Man gb 1949 11 Ladri di biciclette it 1948
select title, country_name, year_released from join on country_code = country where country_code <> 'us'
movies countries
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select title, country_name, year_released from join on country_code = country where country_code <> 'us'
countries
movies joined to countries
gb United Kingdom EUROPE
ru Russia EUROPE us United States AMERICA us United States AMERICA
us United States AMERICA
us United States AMERICA
us United States AMERICA
gb United Kingdom EUROPE
in India ASIA
it Italy EUROPE
hk Hong Kong ASIA
1 Casablanca us 1942 2 Goodfellas us 1990 3 Bronenosets Potyomkin ru 1925 4 Blade Runner us 1982 5 Annie Hall us 1977 6 Ying hung boon sik hk 1986 7 Sholay in 1975 8 On The Waterfront us 1954 9 Lawrence Of Arabia gb 1962 10 The Third Man gb 1949 11 Ladri di biciclette it 1948
movies
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on column1_from_table1 = column5_from_table2 and column2_from_table1 = column1_from_table2
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people peopleid first_name surname born died 5 Claude Rains 1889 1967 10 Lung Ti 1946 15 Carol Reed 1906 1976 20 Ramesh Sippy 1947 25 David Lean 1908 1991 30 Ray Liotta 1954 35 Rutger Hauer 1944
credits movieid peopleid credited_as 1 5 A 6 10 A 10 15 D 7 20 D 9 25 D 137 25 D 2 30 A 4 35 A
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname
join credits
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname
join credits
credits movieid peopleid credited_as 1 5 A 6 10 A 10 15 D 7 20 D 9 25 D 137 25 D 2 30 A 4 35 A 22
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname
join credits
credits movieid peopleid credited_as 1 5 A 6 10 A 10 15 D 7 20 D 9 25 D 137 25 D 2 30 A 4 35 A 23
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname
join credits
credits movieid peopleid credited_as 1 5 A 6 10 A 10 15 D 7 20 D 9 25 D 137 25 D 2 30 A 4 35 A 24
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname distinct
join credits
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First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname distinct
on peopleid = peopleid ? join credits
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natural join
First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname distinct
credits
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natural join
First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname distinct
credits
constraints
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natural join
First name and surname of all directors in the database?
select from people where credited_as = 'D'
first_name, surname distinct
credits
constraints names
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ctry name
countries
id name ctry
people
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ctry name
countries
id name ctry
people
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ctry name
countries
id name ctry
people
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ctry name
countries
id name ctry
people
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select distinct first_name, surname from people join credits where credited_as = 'D'
using (peopleid)
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select distinct first_name, surname from people join credits where credited_as = 'D' on credits.peopleid = people.peopleid
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select distinct first_name, surname from people join credits where credited_as = 'D'
on c.peopleid = p.peopleid
p c
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select distinct p.first_name, p.surname from people p join credits c on c.peopleid = p.peopleid where c.credited_as = 'D'
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Self-Join
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peopleid first_name surname ... fatherid motherid
876 MICHAEL REDGRAVE
1234 VANESSA REDGRAVE 876 932
932 RACHEL KEMPSON
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peopleid first_name surname ... fatherid motherid
876 MICHAEL REDGRAVE
1234 VANESSA REDGRAVE 876 932
932 RACHEL KEMPSON
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peopleid first_name surname ... fatherid motherid
876 MICHAEL REDGRAVE
1234 VANESSA REDGRAVE 876 932
932 RACHEL KEMPSON
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peopleid first_name surname ... fatherid motherid
876 MICHAEL REDGRAVE
1234 VANESSA REDGRAVE 876 932
932 RACHEL KEMPSON
select c.first_name || ' ' || c.surname as person, f.first_name || ' ' || f.surname as father from people as c -- child join people as f -- father on f.peopleid = c.fatherid
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[join operation] select ... from ( )x join ...
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from table1 inner join table2 inner join tablen
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British movie titles with director names?
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credits
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A A D A A A D D A A D A
credits
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select m.title, p.surname
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P.C. Barua
1935
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P.C. Barua
1935
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P.C. Barua 1936 1935
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P.C. Barua 1936 1937
1935
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surname
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select m.title, p.surname
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select m.title, p.surname distinct
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
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Actors in any movie you like?
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select m.year_released, m.country, p.first_name, p.surname from people p join credits c on c.peopleid = p.peopleid join movies m on m.movieid = c.movieid
and c.credited_as = 'A'
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movies m
select m.year_released, m.title, p.first_name, p.surname from inner join on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
credits c
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movies m
select m.year_released, m.title, p.first_name, p.surname from inner join on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'gb'
credits c
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select m.year_released, m.title, p.first_name, p.surname from credits c where c.credited_as = 'D' and m.country = 'gb'
inner join movies m on c.movieid = m.movieid
inner join people p on p.peopleid = c.peopleid
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inner join people p on p.peopleid = c.peopleid
select m.year_released, m.title, p.first_name, p.surname from credits c where c.credited_as = 'D' and m.country = 'gb'
inner join movies m on c.movieid = m.movieid
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select m.year_released, m.title, p.first_name, p.surname from movies m, credits c, people p where c.movieid = m.movieid and p.peopleid = c.peopleid and c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m, credits c, people p where c.movieid = m.movieid and p.peopleid = c.peopleid and c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m, credits c, people p where c.movieid = m.movieid and p.peopleid = c.peopleid and c.credited_as = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m join credits c on c.movieid = m.movieid join people p on p.peopleid = c.peopleid where c.credited_as = 'D' and m.country = 'it'
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select m.year_released, m.title from movies m where m.country = 'it'
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movies people
credits
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movies people
credits
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movies people
credits
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movies people
credits
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select m.year_released, m.title, p.first_name, p.surname from movies m, credits c, people p where c.movieid = m.movieid and p.peopleid = c.peopleid and c.credited_as = 'D' and m.country = 'it'
77 Flickr: John Wigham
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outer join
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outer join inner
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left outer join
right outer join
full outer join
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left outer join
right outer join
full outer join
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Country Name Number of movies
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Country Name Number of movies
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select country as country_code, count(*) as number_of_movies from movies group by country
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select c.country_name, x.number_of_movies from countries c inner join (select country as country_code, count(*) as number_of_movies from movies group by country) x on x.country_code = c.country_code
select country as country_code, count(*) as number_of_movies from movies group by country
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select c.country_name, x.number_of_movies from countries c inner join (select country as country_code, count(*) as number_of_movies from movies group by country) x on x.country_code = c.country_code
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select c.country_name, x.number_of_movies from countries c left outer join (select country as country_code, count(*) as number_of_movies from movies group by country) x on x.country_code = c.country_code
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Display zero when we have no movies from a country?
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select c.country_name, case when x.number_of_movies is null then 0 else x.number_of_movies end number_of_movies from countries c left outer join (select country as country_code, count(*) as number_of_movies from movies group by country) x on x.country_code = c.country_code
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select c.country_name, coalesce(x.number_of_movies, 0) number_of_movies from countries c left outer join (select country as country_code, count(*) as number_of_movies from movies group by country) x on x.country_code = c.country_code
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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from table1 left outer join table2 on
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British movie titles with director names
when available?
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.role = 'D' and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid where c.role = 'D' and m.country = 'gb'
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select a.year_released, a.title, a.first_name, a.surname from (select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid) a
and a.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from (select movieid, year_released, title from movies where country = 'gb') m inner join (select movieid, peopleid from credits where credited_as = 'D') c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid
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select a.year_released, a.title, a.first_name, a.surname from (select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid) a where a.credited_as = 'D' and a.country = 'gb'
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select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m inner join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid
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Which table will be fully shown?
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Which table will be fully shown?
movies
credits
people
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Which table will be fully shown?
movies
credits
people
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Which table will be fully shown?
movies
credits
people
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Which table will be fully shown?
movies
credits
people
Miss?
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select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid
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from movies m left outer join credits c on c.movied = m.movieid
movies credits
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits people
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits people
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits people
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inner join people p on p.peopleid = c.peopleid
from movies m left outer join credits c on c.movied = m.movieid
movies credits people
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select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid people p on p.peopleid = c.peopleid
left outer join
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid people p on p.peopleid = c.peopleid
left outer join
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid people p on p.peopleid = c.peopleid
left outer join
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid
( or a.credited_as is null)
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid
( or a.credited_as is null)
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Hugh Grant
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Movies
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Movies
People
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Movies
People
Credits
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Movies
People
Credits
movieid peopleid
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Movies
People
Credits
movieid peopleid A
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid
( or a.credited_as is null)
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid
( or a.credited_as is null)
A
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select a.year_released, a.title, a.first_name, a.surname from ( ) a where a.credited_as = 'D' and a.country = 'gb'
select m.year_released, m.title, m.country, p.first_name, p.surname, c.credited_as from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid
( or a.credited_as is null)
A
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select m.year_released, m.title, p.first_name, p.surname from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid where (c.credited_as = 'D' or c.credited_as is null) and m.country = 'gb'
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select m.year_released, m.title, p.first_name, p.surname from movies m left outer join credits c on c.movieid = m.movieid left outer join people p on p.peopleid = c.peopleid where (c.credited_as = 'D' or c.credited_as is null) and m.country = 'gb'
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Get movie titles and director name if available
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Get movie titles and director name if available
Get movie titles and people involved, then display if
director known or no people found
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select m.year_released, m.title, p.first_name, p.surname from (select movieid, year_released, title from movies where country = 'gb') m inner join (select movieid, peopleid from credits where credited_as = 'D') c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid
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select m.year_released, m.title, p.first_name, p.surname from (select movieid, year_released, title from movies where country = 'gb') m inner join (select movieid, peopleid from credits where credited_as = 'D') c on c.movieid = m.movieid inner join people p on p.peopleid = c.peopleid
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left outer
select m.year_released, m.title, p.first_name, p.surname from (select movieid, year_released, title from movies where country = 'gb') m join (select movieid, peopleid from credits where credited_as = 'D') c on c.movieid = m.movieid join people p on p.peopleid = c.peopleid
inner
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left outer
select m.year_released, m.title, p.first_name, p.surname from (select movieid, year_released, title from movies where country = 'gb') m join (select movieid, peopleid from credits where credited_as = 'D') c on c.movieid = m.movieid join people p on p.peopleid = c.peopleid
left outer
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Filter close to tables
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Joins
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Joins filtering
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Joins
qualifying
filtering
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select m.title, m.year_released from movies m inner join countries c on c.country_code = m.country where c.country_name = '...'
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select m.title, m.year_released from movies m inner join countries c on c.country_code = m.country where c.country_name = '...'
Filtering
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select m.title, c.country_name from movies m inner join countries c on c.country_code = m.country where m.year_released = ...
Qualifying
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select m.title, c.country_name from movies m inner join countries c on c.country_code = m.country where m.date_released = ...
UNLESS
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select m.title, c.country_name from movies m inner join countries c on c.country_code = m.country where m.date_released = ...
UNLESS
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select distinct m.title, c.country_name from movies m inner join countries c on c.country_code = m.country inner join credits cr on cr.movieid = m.movieid where m.year_released = ...
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Outer joins
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Outer joins
qualifying
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Outer joins filtering is null
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Join
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Join
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Join MORE rows?
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Join MORE rows?
filtering
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Join MORE rows?
filtering
qualifying
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filtering ASAP
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filtering ASAP
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filtering ASAP
qualifying later
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filtering ASAP
qualifying later
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MOVIES
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US MOVIES
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US MOVIES, 1940s
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select * from movies where country_code = 'us' and year_released between 1940 and 1949
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select * from movies where country_code = 'us' and year_released between 1940 and 1949
select * from (select * from movies where country_code = 'us') us_movies where year_released between 1940 and 1949
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select * from movies where country_code = 'us' and year_released between 1940 and 1949
select * from movies where (country = 'us' or country = 'gb') and year_released between 1940 and 1949
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Set operators
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UNION
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US and GB movies, 1940s
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select movieid, title, year_released, country from movies where country = 'us' and year_released between 1940 and 1949
US and GB movies, 1940s
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select movieid, title, year_released, country from movies where country = 'us' and year_released between 1940 and 1949
select movieid, title, year_released, country from movies where country = 'gb' and year_released between 1940 and 1949
US and GB movies, 1940s
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select movieid, title, year_released, country from movies where country = 'us' and year_released between 1940 and 1949
select movieid, title, year_released, country from movies where country = 'gb' and year_released between 1940 and 1949
union
US and GB movies, 1940s
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movies
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movies
premium_movies
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select 'regular' as class, movieid, title, year_released from movies union select 'premium' as class, movieid, title, year_released from premium_movies
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select 'regular' as class, movieid, title, year_released from movies union select 'premium' as class, movieid, title, year_released from premium_movies
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select 'regular' as class, movieid, title, year_released from movies union select 'premium' as class, movieid, title, year_released from premium_movies
all
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current_year_data last_year_data
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current_year_data last_year_data
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current_year_data last_year_data
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current_year_data last_year_data
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current_year_data last_year_data
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current_year_data current_year_data last_year_data
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current_year_data current_year_data last_year_data
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Last year’s views plus year-to-date views
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select movieid, sum(view_count) as view_count from last_year_data group by movieid union select movieid, sum(view_count) as view_count from current_year_data group by movieid
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select movieid, sum(view_count) as view_count from last_year_data group by movieid union select movieid, sum(view_count) as view_count from current_year_data group by movieid
select x.movieid, sum(x.view_count) as view_count from (
) x group by x.movieid
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select movieid, sum(view_count) as view_count from last_year_data group by movieid union select movieid, sum(view_count) as view_count from current_year_data group by movieid
select x.movieid, sum(x.view_count) as view_count from (
) x group by x.movieid
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select movieid, sum(view_count) as view_count from last_year_data group by movieid union select movieid, sum(view_count) as view_count from current_year_data group by movieid
select x.movieid, sum(x.view_count) as view_count from (
) x group by x.movieid
203
Goodfellas 2356
Goodfellas 2356
union
204
Goodfellas 2356
Goodfellas 2356
union
205
Goodfellas 2356
Goodfellas 2356
union all
206
select x.movieid, sum(x.view_count) as view_count from (select 'last year' as period, movieid, sum(view_count) as view_count from last_year_data group by movieid union all select 'this year' as period, movieid, sum(view_count) as view_count from current_year_data group by movieid) x group by x.movieid
207
208
union
209
intersect
210
except / minus
211
intersect
except
212
intersect
except
inner join
213
intersect
except
inner join
outer join
214
country codes that are both in movies and countries
215
select country_code from countries intersect select from movies
country
216
select country_code from countries intersect select from movies
distinct country
217
select c.country_code from countries c inner join ( ) m on m.country = c.country_code
select distinct country from movies
218
select distinct country from movies
219
select country_code from countries except select distinct country from movies
220
select country_code from countries except select distinct country from movies
221
select c.country_code from countries c left outer join (select distinct country from movies) m on m.country = c.country_code where m.country is null
222
Equivalent columns
223
Equivalent columns
Flickr: Tomáš Obšívač
224
Names of the countries in table country but not in table movies?
225
Names of the countries in table country but not in table movies? select c.country_ from countries c left outer join (select distinct country from movies) m on m.country = c.country_code where m.country is null
code
226
name
Names of the countries in table country but not in table movies? select c.country_ from countries c left outer join (select distinct country from movies) m on m.country = c.country_code where m.country is null
227
select * from movies where country_code = 'us'
228
select * from movies where country_code = 'us'
select * from (select * from movies where country_code = 'us') us_movies where year_released between 1940 and 1949
229
select * from movies where country_code = 'us'
select * from (select * from movies where country_code = 'us') us_movies where year_released between 1940 and 1949
230
select * from movies where country_code = 'us'
select * from (select * from movies where country_code = 'us') us_movies where year_released between 1940 and 1949
231
232
233
234
235
236
237
select m.title, m.year_released, c.country_name from movies m join countries c on c.country_code = m.country where m.country <> 'us'
238
select m.title, m.year_released, (select c.country_name from countries c where c.country_code = m.country) as country_name from movies m where m.country <> 'us'
239
select m.title, m.year_released, (select c.country_name from countries c where c.country_code = m.country) as country_name from movies m where m.country <> 'us'
240
us
us
de in
gb
ru
us
in
241
us
us
de in
gb
ru
us
in
select c.country_name from countries c where c.country_code = 'ru'
242
us
us
de in
gb
ru
us
in select c.country_name from countries c where c.country_code = 'in'
243
us
us
de in
gb
ru
us
in
244
us
us
de in
gb
ru
us
in
245
us
us
de in
gb
ru
us
in
select c.country_name from countries c where c.country_code = 'gb'
246
us
us
de in
gb
ru
us
in
select c.country_name from countries c where c.country_code = 'de'
247
us
us
de in
gb
ru
us
in
select c.country_name from countries c where c.country_code = 'in'
248
select m.title, (select c.country_name from countries c where c.country_code = m.country) as country_name from movies m where m.country_code <> 'us'
249
select m.title, c.country_name from movies m left outer join countries c on c.country_code = m.country where m.country <> 'us'
250
from clause
select list
where clause
251
from clause
select list
where clause
252
from clause
select list
where clause
253
in ( ..., ..., ... )
254
in ( ..., ..., ... )
select country, title from movies where (country = 'us' or country = 'gb') and year_released between 1940 and 1949
255
select country, title from movies where country in ('us', 'gb') and year_released between 1940 and 1949
in ( ..., ..., ... )
256
in ( ..., ..., ... )
257
in (select col from ... where ...)
258
select country, year_released, title from movies where country in (select country_code from countries
259
(col1, col2) in (select col3, col4 from t
260
in
distinct
261
select country, year_released, title from movies where country in (select country_code from countries
262
select m.country, m.year_released, m.title from movies m inner join (select country_code from countries on c.country_code = m.country
263
select m.country, m.year_released, m.title from movies m inner join (select country_code from countries on c.country_code = m.country
264
no distinct Demonstrably unique
265
select country, title from ... inner join (select distinct ... from ...) on ...
266
select country, title from ... inner join (select distinct ... from ...) on ...
where col in (select distinct ... from ... )
267
Explicit is better than
Implicit
268
duplicate rows?
269
duplicate rows?
nulls?
270
col in ('a', 'b', 'c')
(col = 'a' or col = 'b' or col = 'c')
=
271
col in ('a', 'b', null)
(col = 'a' or col = 'b' or col = null)
=
272
col in ('a', 'b', null)
(col = 'a' or col = 'b' or col = null)
=
always
false
273
Augustus de Morgan (1806-1871)
274
col not in ('a', 'b', null)
(col <> 'a' and col <> 'b' and col <> null)
=
275
col not in ('a', 'b', null)
(col <> 'a' and col <> 'b' and col <> null)
=
always
false
276
col not in ('a', 'b', null)
(col <> 'a' and col <> 'b' and col <> null)
=
277
select * from people where first_name not in (select first_name from people where born < 1950)
278
select * from people where first_name not in (select first_name from people where born < 1950 and first_name is not null)
279
select p.* from people p left outer join (select first_name, from people where born <= 1950) p2 on p2.first_name = p.first_name where p2.first_name is null
280
select p.* from people p left outer join (select first_name, from people where born <= 1950) p2 on p2.first_name = p.first_name where p2.first_name is null
281
select p.* from people p left outer join (select first_name, from people where born <= 1950) p2 on p2.first_name = p.first_name where p2.first_name is null and p.born >= 1950
282
from clause
select list
where clause
283
exists
284
exists
not exists
285
and exists (select ... ...)
286
select distinct m.title from movies m where exists (select null from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
287
select distinct m.title from movies m where exists (select null from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
288 Flickr: Kevin N. Murphy
289
select m.title from movies m where exists (select from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
c.movieid
290
select m.title from movies m where exists (select from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
p.surname
291
select m.title from movies m where exists (select from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
1
292
'Insert anything here'
select m.title from movies m where exists (select from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
293
select m.title from movies m where exists (select from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970 and c.movieid = m.movieid)
null
294
(select null from credits c inner join people p on p.peopleid = c.peopleid where c.created_as = 'A' and p.born >= 1970 and c.movieid = current movieid)
movies
295
(select null from credits c inner join people p on p.peopleid = c.peopleid where c.created_as = 'A' and p.born >= 1970 and c.movieid = current movieid)
movies
296
(select null from credits c inner join people p on p.peopleid = c.peopleid where c.created_as = 'A' and p.born >= 1970 and c.movieid = current movieid)
movies
297
(select null from credits c inner join people p on p.peopleid = c.peopleid where c.created_as = 'A' and p.born >= 1970 and c.movieid = current movieid)
movies
298
(select null from credits c inner join people p on p.peopleid = c.peopleid where c.created_as = 'A' and p.born >= 1970 and c.movieid = current movieid)
movies
299
select distinct m.title from movies m where m.movieid in (select distinct c.movieid from credits c inner join people p on p.peopleid = c.peopleid where c.credited_as = 'A' and p.born >= 1970)
300
correlated
uncorrelated
301
correlated
uncorrelated from
302
correlated
uncorrelated from
303
It depends ...
Flickr: Alan Cleaver 303
304
Joins on common values. Inner: match only Outer: complete with nulls
305
Joins on common values. Inner: match only Outer: complete with nulls Order of tables and place of conditions matter with outer joins, not with inner joins.
306
Joins on common values. Inner: match only Outer: complete with nulls Order of tables and place of conditions matter with outer joins, not with inner joins. Set operators also allow to combine datasets. Only UNION provides functionality that no operator provide.
307
Joins on common values. Inner: match only Outer: complete with nulls Order of tables and place of conditions matter with outer joins, not with inner joins. Set operators also allow to combine datasets. Only UNION provides functionality that no operator provide. Subqueries can appear in the SELECT (correlated), in the FROM (uncorrelated), in the WHERE (either). Beware of nulls.
top related