Middle

Nepieciešams uzrakstīt vaicājumu, kas atgriezīs māksliniekus un viņu agrākos albumus formātā <Mākslinieka vārds> <Pirmā albuma nosaukums> <Pirmā albuma izlaišanas datums>. create table Artists ( id serial primary key, name varchar(255) not null ); create table Albums ( id serial primary key, artistId int not null references Artists(id), name varchar(255) not null, release_date timestamp not null ); insert into Artists(name) values ('2Pac'), ('Wu-Tang Clan'), ('Eminem'); insert into Albums(name, artist_id, release_date) values ('The Slim Shady LP', 3, '[phone]'), ('Me Against The World', 1, '[phone]'), ('The Eminem Show', 3, '[phone]'), ('Enter The Wu-Tang Clan', 2, '[phone]'), ('Recovery', 3, '[phone]'), ('The W', 2, '[phone]'), ('2Pacalypse Now', 1, '[phone]'); select a.name, al.name, al.release_date from Artists as a join Albums as al on a.Id = al.artistId where al.release_date = ( select min(release_date) from Albums where artist_id = a.id ); with cte as ( select artist_id, min(release_date) as first_album_date from albums group by artist_id ) select a.Id, a.Name, fa.first_album_date from Artists a join cte as fa on a.Id = fa.artist_id;

sobes.tech AI

Atbilde no AI

Lai iegūtu māksliniekus ar viņu agrākajiem albumiem, jūs varat izmantot vaicājumu ar apakšvaicājumu, kas izvēlas minimālo albuma izlaišanas datumu katram māksliniekam, un pēc tam to savienot ar albumu tabulu, lai iegūtu albuma nosaukumu.

Piemēra vaicājums:

select
    a.name as artist_name,
    al.name as first_album_name,
    al.release_date as first_album_date
from Artists a
join Albums al on a.id = al.artistId
where al.release_date = (
    select min(release_date)
    from Albums
    where artistId = a.id
)
order by a.name;

Alternatīvi, jūs varat izmantot CTE, lai aprēķinātu minimālo datumu, un pēc tam to savienot ar albumu tabulu:

with first_albums as (
    select artistId, min(release_date) as first_album_date
    from Albums
    group by artistId
)
select
    a.name as artist_name,
    al.name as first_album_name,
    al.release_date as first_album_date
from Artists a
join first_albums fa on a.id = fa.artistId
join Albums al on al.artistId = fa.artistId and al.release_date = fa.first_album_date
order by a.name;

Šis vaicājums atgriezīs mākslinieka vārdu, viņa pirmā albuma nosaukumu un pirmā albuma izlaišanas datumu.

Iepriekšējais Tālāk