SQL请求多个选择

SQL请求：

客户的numClient，nomClient，numClient，numTel，订购的总金额

对于prixUnitaire>2000的物品dispendic，prixUnitaire<1500的物品modic总订购量

对于订购大量dispendic文章的客户<订购modic文章的数量

以下是相关的表格

• 客户机（numClient、nomClient、numTel）
• 文章（法令、说明、原则、条款）
• 命令（numCde、dateCde、numClient）
• 木质材料（numCde#，numArticle#，qté）
• 利夫莱森（努姆利夫，达特利夫）
• 详细信息（numLiv、numCde、numArticle、qtéLiv）
我的理解：
• 金额是指项目数量（数量），而不是总价值（数量*价格）
该疑问只需要考虑命令，所以“命令”，而不是“LIFRAISY”。
• dispendic指价格>2000；modic表示价格<1500。（我不知道 了解这些词；它们是否特定于您的业务？）
您没有提到正在使用哪个数据库。我使用了PostgreSQL，但它都是标准SQL，所以应该可以在任何标准关系数据库上使用
设立

create table client
(
    num_client   integer,
    nom_client   varchar(16),
    num_tel      varchar(20),
    constraint primary_key_client primary key (num_client)
);

create table article
(
    num_article        integer,
    description        varchar(16),
    prix_unitaire      decimal(9,2),
    quantite_en_stock  integer,
    constraint primary_key_article primary key (num_article)
); 

create table commande
(
    num_commande       integer,
    date_commande      date,
    num_client         integer,
    constraint primary_key_commande primary key (num_commande),
    constraint foreign_key_commande_client foreign key (num_client) references client(num_client)
);

create table ligne_commande
(
    num_commande       integer,
    num_article        integer,
    quantite           integer,
    constraint foreign_key_ligne_commande_commande foreign key (num_commande) references commande(num_commande),
    constraint foreign_key_ligne_commande_article foreign key (num_article) references article(num_article)
);

insert into client (num_client, nom_client, num_tel) values (123, 'Dubois', '1 41 17 86 62');
insert into client (num_client, nom_client, num_tel) values (456, 'Bochet', '1 35 32 65 58');

insert into article (num_article, description, prix_unitaire, quantite_en_stock) values (79362, 'chaise', 1499.00, 36);
insert into article (num_article, description, prix_unitaire, quantite_en_stock) values (83746, 'placard', 2001.00, 14);

insert into commande (num_commande, date_commande, num_client) values (10030, '2018-01-13', 123);
insert into commande (num_commande, date_commande, num_client) values (10019, '2018-01-12', 456);

insert into ligne_commande (num_commande, num_article, quantite) values (10030, 79362, 4);
insert into ligne_commande (num_commande, num_article, quantite) values (10030, 83746, 1);
insert into ligne_commande (num_commande, num_article, quantite) values (10019, 79362, 1);
insert into ligne_commande (num_commande, num_article, quantite) values (10019, 83746, 1);
insert into ligne_commande (num_commande, num_article, quantite) values (10019, 83746, 1);    

质疑

select
    a.num_client,
    a.nom_client,
    a.num_tel,
    dispendic.sum_quantite as dispendic_amount,
    modic.sum_quantite as modic_amount
from
    client a
    join 
    commande b
    on a.num_client = b.num_client
    join
    (
        select
            num_commande,
            sum(quantite) as sum_quantite
        from
            ligne_commande w
            join
            article x
            on w.num_article = x.num_article
        where
            x.prix_unitaire < 1500
        group by
            num_commande
    ) modic
    on b.num_commande = modic.num_commande
    join
    (
        select
            num_commande,
            sum(quantite) as sum_quantite
        from
            ligne_commande w
            join
            article x
            on w.num_article = x.num_article
        where
            x.prix_unitaire > 2000
        group by
            num_commande
    ) dispendic
    on b.num_commande = dispendic.num_commande
where
    dispendic.sum_quantite < modic.sum_quantite;

 num_client | nom_client |    num_tel    | dispendic_amount | modic_amount 
------------+------------+---------------+------------------+--------------
        123 | Dubois     | 1 41 17 86 62 |                1 |            4
(1 row)