X sql解惑 25 里程碑问题 答案

sql解惑 25 里程碑问题 答案

create table servicesschedule(
shop_id char(3) not null,
order_nbr char(10) not null,
sch_seq number not null check(sch_seq in (1,2,3)),
service_type char(2) not null,
sch_date date,
primary key(shop_id,order_nbr,sch_seq));

drop table sch_seq;
create table sch_seq_desc(
sch_seq number not null,
sch_desc varchar2(20)
);

insert into sch_seq_desc values(1,'processed');
insert into sch_seq_desc values(2,'completed');
insert into sch_seq_desc values(3,'confirmed');


insert into servicesschedule values('002','4155526710',1,'01',date'1994-07-16');
insert into servicesschedule values('002','4155526710',2,'01',date'1994-07-30');
insert into servicesschedule values('002','4155526710',3,'01',date'1994-10-01');
insert into servicesschedule values('002','4155526711',1,'01',date'1994-07-16');
insert into servicesschedule values('002','4155526711',2,'01',date'1994-07-30');
insert into servicesschedule values('002','4155526711',3,'01',null);

select * from sch_seq_desc;
select * from servicesschedule;





select a.order_nbr,
min(case when sch_desc = 'processed' then sch_date end) as processed,
min(case when sch_desc = 'completed' then sch_date end) as completed,
min(case when sch_desc = 'confirmed' then sch_date end) as confirmed
from servicesschedule a,sch_seq_desc b
where a.sch_seq=b.sch_seq 
  and service_type= '01'
group by order_nbr ;


==============================================================================================
==============================================================================================




SQL> select * from servicesschedule;

SHOP_I ORDER_NBR               SCH_SEQ SERV SCH_DATE
------ -------------------- ---------- ---- ------------
002    4155526710                    1 01   16-JUL-94
002    4155526710                    2 01   30-JUL-94
002    4155526710                    3 01   01-OCT-94
002    4155526711                    1 01   16-JUL-94
002    4155526711                    2 01   30-JUL-94
002    4155526711                    3 01

6 rows selected.



select * from sch_seq_desc;

   SCH_SEQ SCH_DESC
---------- ----------------------------------------
         1 processed
         2 completed
         3 confirmed




select a.order_nbr,
min(case when sch_desc = 'processed' then sch_date end) as processed,
min(case when sch_desc = 'completed' then sch_date end) as completed,
min(case when sch_desc = 'confirmed' then sch_date end) as confirmed
from servicesschedule a,sch_seq_desc b
where a.sch_seq=b.sch_seq 
  and service_type= '01'
group by order_nbr ;  

ORDER_NBR            PROCESSED    COMPLETED    CONFIRMED
-------------------- ------------ ------------ ------------
4155526710           16-JUL-94    30-JUL-94    01-OCT-94
4155526711           16-JUL-94    30-JUL-94