Oracle数据库10G查询待解决

Question

create table customer
    (cust_id    integer     not null,
    cust_name   char(20)    not null ,
    cust_address    varchar2(200)   ,
    emp_id      integer     not null,
        constraint pk_customer primary key(cust_id)
    );

create table account
    (account_number integer     not null,
    account_balance number(8,2) not null,
    constraint pk_acount primary key(account_number)
    );
create table has
    (cust_id    integer     not null,
        account_number  integer     not null,
        constraint pk_has primary key(cust_id, account_number)
        );
alter table has
add constraint fk_account_has foreign key(account_number) 
references account(account_number);

alter table has 
add constraint fk_customer_has foreign key(cust_id) 
references customer(cust_id);

alter table customer 
add constraint fk_employee_customer foreign key(emp_id) 
references employee(emp_id);

Q1显示所有关于客户的信息，帐号分别是101个和102号。

Q2显示帐户余额大于500的所有客户的帐号和客户ID。

Q3显示与500不同帐户余额的客户的所有信息。

Answer 1

会是这样的：

select c.cust_id, c.cust_address, c.cust_address
from customer c join has h on h.cust_id = c.cust_id
where h.account_number in (101, 102);

我建议您立即停止阅读，然后--看看第一个示例--尝试自己编写接下来的2个查询。

select c.cust_id, h.account_Number
from customer c join has h on h.cust_id = c.cust_id
join account a on a.account_number = h.account_number
where a.account_balance > 500;

select c.cust_id, c.cust_address, c.cust_address
from customer c join has h on h.cust_id = c.cust_id
join account a on a.account_number = h.account_number
where a.account_balance <> 500;