利用户外俱乐部和产品数据库创建一个PL / SQL匿名块程序单元，该单元列出product_name属性值和需求状态文本显示。需求状态文本显示是通过计算到目前为止已订购产品的次数来确定的。需求状态文本显示将为“低需求”或“高需求”。如果订购的产品少于2次，则显示低需求。如果产品已订购两次以上，则会显示“高需求”。问题扩展：由于不携带需求量低的产品的业务规则，请将需求量低的产品的价格降低1美元。
考虑到它甚至无法运行，我知道我的代码是错误的，但是我对此感到很困惑。
set serveroutput on
clear screen
declare
product_name string;
demand_status string;
begin
select product_name into product_name from product;
select product_id into demand_status from order_details ;
dbms_output.put_line('Product name' || 'Demand status');
dbms_output.put_line('------------' || '--------------');
dbms_output.put_line(product_name || demand_status);
end;
结果应如下所示：
Product Name Demand Status
------------ -------------
Beginner's Ski Boot Low Demand
Intermediate Ski Boot High Demand
Pro Ski Boot Low Demand
Beginner's Ski Pole Low Demand
Intermediate Ski Pole Low Demand
Pro Ski Pole High Demand
Road Bicycle Low Demand
Mountain Bicycle Low Demand
Tire Pump Low Demand
Water Bottle High Demand
Bicycle Tires Low Demand
Bicycle Helmet Low Demand
Order_Details table Product table
这是数据库表的代码：
drop table order_details;
drop table product_order;
drop table club_membership;
drop table purchase_order;
drop table product;
drop table customer;
drop table club_activity;
drop table sporting_clubs;
drop table supplier;
drop sequence club_sequence;
drop sequence product_id_sequence;
drop sequence customer_sequence;
drop sequence membership_sequence;
drop sequence product_order_sequence;
drop sequence supplier_sequence;
drop sequence po_sequence;
create table sporting_clubs
(club_id number(3)constraint sporting_clubs_pk primary key,
name varchar2(30),
street varchar2(30),
city varchar2(15),
state char(2),
zip number(5),
phone varchar2(10));
create table club_activity
(club_id number(3)constraint club_activity_fk references sporting_clubs,
activity varchar2(15),
constraint club_activity_pk primary key (club_id,activity));
create table supplier
(supplier_id varchar2(4) constraint supplier_pk primary key,
name varchar2(30),
street varchar2(30),
city varchar2(15),
state char(2),
zip number(5),
phone varchar2(10));
create table product
(product_id number(5) constraint product_pk primary key,
product_name varchar2(30),
quantity_in_stock number(3),
reorder_point number(2),
price number(5,2),
supplier_id varchar2(4) constraint product_fk references supplier,
reorder_qty number(2));
create table purchase_order
(po_no varchar2(4) constraint purchase_order_pk primary key,
po_date date,
product_id number(5) constraint purchase_order_fk1 references product,
quantity number(3),
supplier_id varchar2(4) constraint purchase_order_fk2 references supplier);
create table customer
(customer_id number(3) constraint customer_pk primary key,
first_name varchar2(10),
last_name varchar2(10),
street varchar2(30),
city varchar2(15),
state char(2)default 'MO',
zip number(5),
phone varchar2(10));
create table club_membership
(membership_id number(5) constraint club_membership_pk primary key,
membership_date date,
duration number(2),
amount number(4),
payment_type varchar2(5)constraint membership_payment_type_ck check ((payment_type = 'CC') or (payment_type = 'Check')),
club_id number(3) constraint club_membership_fk1 references sporting_clubs,
customer_id number(3) constraint club_membership_fk2 references customer);
create table product_order
(order_id number(4) constraint product_order_pk primary key,
order_date date,
ship_date date,
payment_type varchar2(5)constraint prod_order_payment_type_ck check ((payment_type = 'CC') or (payment_type = 'Check')),
total number (6,2),
customer_id number(3) constraint product_order_fk1 references customer);
create table order_details
(order_id number(4),
product_id number(5),
quantity number(2),
constraint order_details_pk primary key (order_id,product_id),
constraint order_details_fk1 foreign key (order_id) references product_order,
constraint order_details_fk2 foreign key (product_id) references product);
create sequence club_sequence
start with 100
increment by 10
nocache;
insert into sporting_clubs
values(club_sequence.nextval, 'Hillside Mountain Club', '1 Winona St','Wichita','KS',34342,'3163997676');
insert into sporting_clubs
values(club_sequence.nextval, 'Branson Climbing Club', '2 Sherwood Dr.','Branson','MO',65670,'4174485676');
insert into sporting_clubs
values(club_sequence.nextval, 'Cherokee Rafting Club', '44 Kent Ave.','St. Charles','MO',66572,'3147780870');
insert into sporting_clubs
values(club_sequence.nextval, 'White Plains Club', '225 Tracy St.','New York','NY',13567,'2126678090');
insert into club_activity
values(100,'Hiking');
insert into club_activity
values(100,'Climbing');
insert into club_activity
values(100,'Walking');
insert into club_activity
values(110,'Hiking');
insert into club_activity
values(110,'Climbing');
insert into club_activity
values(110,'Conservation');
insert into club_activity
values(110,'Walking');
insert into club_activity
values(120,'Conservation');
insert into club_activity
values(120,'Canoeing');
insert into club_activity
values(130,'Conservation');
insert into club_activity
values(130,'Canoeing');
insert into club_activity
values(130,'Walking');
create sequence supplier_sequence
start with 500
increment by 10
nocache;
insert into supplier
values('S'||supplier_sequence.nextval,'Hillside Ski','2717 S. Western Ave.','Los Angeles','CA',90006,'7146654959');
insert into supplier
values('S'||supplier_sequence.nextval,'Tiger Mountain','2600 S. Vermont Ave.','Los Angeles','CA',90006,'7143327878');
insert into supplier
values('S'||supplier_sequence.nextval,'Asha Outdoor','44 S. LaSalle St.','Chicago','IL',60603,'3125554678');
insert into supplier
values('S'||supplier_sequence.nextval,'Sheraton Recreation','225 Tracy St.','New York','NY',13567,'2128889569');
create sequence product_id_sequence
start with 10010
increment by 1
nocache;
insert into product
values(product_id_sequence.nextval,'Beginner''s Ski Boot',20,5,9.75,'S500',25);
insert into product
values(product_id_sequence.nextval,'Intermediate Ski Boot',18,5,12.99,'S500',20);
insert into product
values(product_id_sequence.nextval,'Pro Ski Boot',21,7,15.49,'S510',25);
insert into product
values(product_id_sequence.nextval,'Beginner''s Ski Pole',15,3,25.49,'S500',20);
insert into product
values(product_id_sequence.nextval,'Intermediate Ski Pole',20,3,29.99,'S520',22);
insert into product
values(product_id_sequence.nextval,'Pro Ski Pole',21,5,34.99,'S530',25);
insert into product
values(product_id_sequence.nextval,'Road Bicycle',15,4,34.95,'S520',18);
insert into product
values(product_id_sequence.nextval,'Mountain Bicycle',19,4,49.99,'S520',20);
insert into product
values(product_id_sequence.nextval,'Tire Pump',8,2,7.99,'S530',10);
insert into product
values(product_id_sequence.nextval,'Water Bottle',25,4,2.49,'S510',25);
insert into product
values(product_id_sequence.nextval,'Bicycle Tires',30,5,4.99,'S500',33);
insert into product
values(product_id_sequence.nextval,'Bicycle Helmet',23,6,10.95,'S510',25);
create sequence po_sequence
start with 11
nocache;
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('5/25/12','mm/dd/yy'),10011,20,'S500');
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('5/12/12','mm/dd/yy'),10015,25,'S530');
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('6/25/12','mm/dd/yy'),10011,20,'S500');
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('6/15/12','mm/dd/yy'),10018,10,'S530');
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('7/10/12','mm/dd/yy'),10015,25,'S530');
insert into purchase_order
values('PO'||po_sequence.nextval,to_date('7/25/12','mm/dd/yy'),10019,25,'S510');
create sequence customer_sequence
start with 101
nocache;
insert into customer
values(customer_sequence.nextval,'Jack','Russell','25 North Madison Ave.','Springfield','MO',65807,'4178823434');
insert into customer
values(customer_sequence.nextval,'Betty','Trumbell','550 South Court Dr.','St. Louis','MO',63140,'3125556670');
insert into customer
values(customer_sequence.nextval,'Anil','Kaul','400 South Circle St.','Kansas City','MO',64530,'4316667070');
insert into customer
values(customer_sequence.nextval,'Tom','Wiley','1500 North Grand St.','Springfield','MO',65810,'4178825560');
insert into customer
values(customer_sequence.nextval,'Sharon','Stone','200 West Wagner St.','Springfield','MO',65807,'4176668890');
create sequence membership_sequence
start with 10010
increment by 10
nocache;
insert into club_membership
values(membership_sequence.nextval,to_date('6/12/12','mm/dd/yy'),4,200,'CC',100,101);
insert into club_membership
values(membership_sequence.nextval,to_date('6/15/12','mm/dd/yy'),2,100,'Check',110,102);
insert into club_membership
values(membership_sequence.nextval,to_date('6/21/12','mm/dd/yy'),5,250,'Check',120,103);
create sequence product_order_sequence
start with 1001
nocache;
insert into product_order
values(product_order_sequence.nextval,to_date('5/27/12','mm/dd/yy'),to_date('6/1/12','mm/dd/yy'),'CC',134.95,102);
insert into product_order
values(product_order_sequence.nextval,to_date('5/28/12','mm/dd/yy'),to_date('6/2/12','mm/dd/yy'),'CC',134.85,103);
insert into product_order
values(product_order_sequence.nextval,to_date('5/28/12','mm/dd/yy'),to_date('6/3/12','mm/dd/yy'),'Check',12.45,104);
insert into product_order
values(product_order_sequence.nextval,to_date('6/5/12','mm/dd/yy'),to_date('6/10/12','mm/dd/yy'),'CC',44.43,105);
insert into product_order
values(product_order_sequence.nextval,to_date('6/6/12','mm/dd/yy'),to_date('6/8/12','mm/dd/yy'),'Check',52.48,103);
insert into product_order
values(product_order_sequence.nextval,to_date('6/8/12','mm/dd/yy'),to_date('6/12/12','mm/dd/yy'),'CC',131.94,104);
insert into order_details values(1001,10011,2);
insert into order_details values(1001,10015,3);
insert into order_details values(1002,10011,5);
insert into order_details values(1002,10016,2);
insert into order_details values(1003,10019,5);
insert into order_details values(1004,10018,3);
insert into order_details values(1004,10011,1);
insert into order_details values(1004,10019,3);
insert into order_details values(1005,10017,1);
insert into order_details values(1005,10019,1);
insert into order_details values(1005,10021,1);
insert into order_details values(1006,10012,4);
insert into order_details values(1006,10015,2);
commit;
答案 0 :(得分：2)
首先，您必须计算每个产品的订单数。因此您可以将两个表加入按产品分组的结果。
select product_name
,count(1) as cnt_orders
from product p
join order_details o on p.product_id = o.product_id
group by p.product_name;
使用计数器列可以获取值“低需求”或“高需求”。例如
case when t.cnt_orders < 2 then 'Low' else 'High' end as "Demand status"
最后，您可以迭代结果并可以打印出结果。这是您可以执行的方法。这并不涵盖扩展的问题，它只是像您的示例中那样打印列表。
BEGIN
dbms_output.put_line(RPAD('Product name',28,' ') || 'Demand status');
dbms_output.put_line('------------' || '--------------');
for rec in (select t.product_name
,case
when t.cnt_orders < 2 then
'Low'
else
'High'
end as DemandStatus
from (select product_name
,count(1) as cnt_orders
from product p
left join order_details o on p.product_id = o.product_id
group by p.product_id
,p.product_name
order by p.product_id) t)
LOOP
dbms_output.put_line(RPAD(rec.product_name,28,' ') || rec.DemandStatus);
END LOOP;
END;
/
dbms_output: Product name Demand status ------------ -------------- Beginner's Ski Boot Low Intermediate Ski Boot High Pro Ski Boot Low Beginner's Ski Pole Low Intermediate Ski Pole Low Pro Ski Pole High Road Bicycle Low Mountain Bicycle Low Tire Pump Low Water Bottle High Bicycle Tires Low Bicycle Helmet Low >
db <>提琴here
答案 1 :(得分：0)
declare
cursor p_cur is
select product_id, product_name
from product;
p_row p_cur%rowtype;
product_count integer;
pname char(25);
begin
dbms_output.put_line('Product Name Demand Status');
dbms_output.put_line('------------ -------------');
for p_row in p_cur
loop
select count(*) into product_count
from order_details
where product_id = p_row.product_id;
pname := p_row.product_name;
if product_count < 2 then
dbms_output.put_line(pname||'Low Demand');
update product
set price = price - 1
where product_id = p_row.product_id;
else
dbms_output.put_line(pname||'High Demand');
end if;
end loop;
end;