Igor, et al.
The first time I posted the question took over 5 hours to get there and back
to me. So I assumed that the first question was lost and reposted the question
with a small update to reflect the actual problem that wasn't represented in
the first case..
My mistake.
The 22 is kind of like a time stamp.. (or you could just as easily add
another column indicative of a timestamp.
insert into stack values (1, 1234);
insert into stack values (2, 1234);
insert into stack values (6, 1234);
insert into stack values (9, 1234);
insert into stackpop values (12, 1234) ;
insert into stackpop values (14, 1234) ;
insert into stackpop values (18, 1234) ;
insert into stack values (22, 1234);
so that 12 should pop 9, 14 pops 6 and 18 pops 2 leaving the stack with 1
and 22.
I haven't had a chance to review your solution. However, I did come up with
one of my own for the first case, And a processing solution where the stackpop
is queried and the stack table is processed based upon the query results...
Solution 1:
create temp table t_stack (nid integer primary key autoincrement
, id integer, value integer);
insert into t_stack (id, value)
select * from stack
where value = 1234
order by id desc;
create temp table t_pop(nid integer primary key autoincrement
, id integer, value integer);
insert into t_pop (id, value) select * from stackpop order by id asc;
select sp.id, s.id from t_pop sp, t_stack s where sp.nid = s.nid;
Solution 2:
for each row in stackpop sp:
1. stack_pop_id = select max(id) from stack where id < sp.id
2. delete the row from stack where id = stack_pop_id
loop
Thanks Igor for your suggestions... I agree using sql to implement a stack is
pretty bad and maybe the best solution is to do this programatically.
Igor Tandetnik <[EMAIL PROTECTED]> wrote: Ken wrote:
> Does anyone have ideas on how to implement a stack using sql ????
> Given the following tables and data:
>
> create table stack( id integer primary key, value integer);
> create table stackpop ( id integer primary key, value integer );
>
> begin;
> insert into stack values (1, 1234);
> insert into stack values (2, 1234);
> insert into stack values (6, 1234);
> insert into stack values (9, 1234);
> insert into stack values (22, 1234);
>
> insert into stackpop values (12, 1234) ;
> insert into stackpop values (14, 1234) ;
> insert into stackpop values (18, 1234) ;
> commit;
>
> Do you have any ideas for a select that will return the stackpop and
> stack id's paired as follows:
> 12 | 9
> 14 | 6
> 18 | 2
What's the logic supposed to be here? Why is the stack record with id=22
omitted?
I believe I've answered this question the first time you aked it. Have
you found the answer lacking? In what respect?
Igor Tandetnik
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