【SQL解惑】谜题7：跟踪投资组合

解惑一：

--创建数据源
create

table
Porfolios
(
       file_id_1

integer
not
null
primary
key,
       stuff_1

char(15)

not
null
)

insert

into
Porfolios(file_id_1,stuff_1)
values
(222,'stuff'),
(223,'old
stuff'),
(224,'new
stuff'),
(225,'borrowed
stuff'),
(322,'blue
stuff'),
(323,'purple
stuff'),
(324,'red
stuff'),
(325,'green
stuff'),
(999,'yellow
stuff')

create

table
Succession
(
       chain

integer
not
null,
       next_1

integer
not
null,
       file_id_1

integer
not
null
references
Porfolios(file_id_1),
       suc_date

date
not
null,
       primary

key(chain,next_1)
)

insert

into
Succession(chain,next_1,file_id_1,suc_date)
values
(1,0,222,'2017-11-01'),
(1,1,223,'2017-11-02'),
(1,2,224,'2017-11-04'),
(1,3,225,'2017-11-05'),
(1,4,999,'2017-11-25'),
(2,0,322,'2017-11-01'),
(2,1,323,'2017-11-02'),
(2,2,324,'2017-11-04'),
(2,3,322,'2017-11-05'),
(2,4,323,'2017-11-12'),
(2,5,999,'2017-11-25')

---不论select语句上的投资组合是什么，都能够select出最新的投资组合
select

distinct
p1.file_id_1,stuff_1,suc_date
from

Porfolios
as
p1,Succession

as
s1
where

p1.file_id_1

=
s1.file_id_1
and

next_1
=
(select

max(next_1)

from
Succession
as
s2
where
s1.chain

=
s2.chain)
----需要能够对一系列文档重新生成审计痕迹
select

chain,next_1,p1.file_id_1,stuff_1,suc_date
from

Porfolios
as
p1,Succession

as
s1
where

s1.file_id_1

=
p1.file_id_1
order

by
chain,next_1
----需要记录这个投资组合替代的是哪一个投资组合
begin
declare

@my_file_id
integer 

---声明一个需要查询的文档号
select

s1.file_id_1,'
superseded ',s2.file_id_1,'
on ',s2.suc_date
from

Succession
as
s1,Succession

as
s2
where

s1.chain

=
s2.chain
and

s1.next_1

=
s2.next_1

+
1
and

s1.file_id_1

=
@my_file_id
end
----需要能够恢复某个投资组合
begin
declare

@old_file_id
integer  

----声明一个旧文档号
declare

@my_file_id
integer  

----声明一个新文档号
declare

@new_suc_date
date    

----声明一个新文档号的日期
insert

into
Porfolios
values
(@my_file_id,'stciky
stuff')
insert

into
Succession
(chain,

next_1,

file_id_1,

suc_date)
values

((select

distinct
chain
                

from
Succession
as
s1
               

where
s1.file_id_1

=
@old_file_id),
              (select

max(next_1)

+
1
                

from
Succession
as
s1
               

where
s1.chain

=
(select

distinct
chain
                                                 

from
Succession
as
s2
                                                

where
file_id_1
=
@my_file_id)),
                                                 @my_file_id,@new_suc_date)
end