Help with sql - Left Join

Question

Hi,
Below are the details of what I am attempting to do.
DB version: 10.2.0.4.0
Sample Table Definition
create table t_cnf
conf_id number,
conf_value number,
conf_cat_id number,
actv_flg    char(1)
create table t_int_act
int_acc_id   number,
frst_mrch_id number,
create_date  date
create table t_int_act_cast
int_acc_id   number,
cast_id      number
create t_cast_alt_nmnt
cas_alt_nmt_id number,
cas_alt_id     number,
cast_id        number,
enrl_flg       char(1),
src_id         number
);Sample Data
insert into t_cnf values (1, 78965098, 12, 'Y');
insert into t_cnf values (1, 78965098, 13, 'Y');
insert into t_int_act values (234,78965098, trunc(sysdate) - 1);
insert into t_int_act_cast values (234, 560432);
insert into t_cas_alt_nmnt values (1, 2, 560432, 'Y', 2); Need to fetch all cast_ids that are not in t_cast_alt_nmnt or cast_ids that are present in t_cast_alt_nmnt but have t_cast_alt_nmnt.enrl_flg = 'N' and t_cast_alt_nmnt.cast_alt_id in (2,3) and t_cast_alt_nmnt.src_id <> 2
for t_int_act.frst_mrch_ids matching t_cnf.conf_vale
Records fetch will insert a record into t_cast_alt_nmnt with css_alt_id 2 or 3 (determined by pe_or_pd).
I attempted to write below sql. This works fine when cast_id does not exists in t_cast_alt_nmnt but will not return correct results when there is a record in t_cast_alt_nmnt matching above criteria.
select
    iac.cast_id                            cast_id,
    sysdate                                upd_date,               
    case
        when c.conf_cat_id = 12 then 2
        when c.conf_cat_id = 13 then 3
    end
        pe_or_pd           
from
    t_cnf                  c
join    
    t_int_act          ia
on
    ia.frst_mrch_id = c.conf_value
join              
    t_int_act_cast iac
on
    ia.int_acc_id = iac.int_acc_id
left join       
    t_cast_alt_nmnt     can
on
    can.cast_id = iac.cast_id     and
    can.enrl_flg = 'N'            and
    can.cas_alt_id in (2,3)       and
    can.src_id <> 2      
where                 
    c.conf_cat_id              in (12,13)                           and
    c.actv_flg                 = 'Y'                                and
    -- Fetch all new customer created day before.   
    ia.create_date             >= trunc(sysdate) - 1                   
    Expected results
With no cast_id record in t_cast_alt_nmnt
cast_id upd_date pe_or_pd
560432 4/19/2012 2
560432 4/19/2012 3
With cast_id record in t_css_alt_nmt (insert provided)
cast_id upd_date pe_or_pd
560432 4/19/2012 3
Appreciate your help
Edited by: user572194 on Apr 19, 2012 1:04 PM

Answer 1

Thanks Frank for taking time to look into this and providing sql. I will test is against use cases (mentioned below).
And I apologize for the typos. I had to change table and column names as it is policy of our company not to post data model details in public forums.
Requirement:
1. New cast ids will be added daily and these will get inserted into t_int_act and t_int_act_cas
2. t_cnf has 2 conf_cat_id configured 12 and 13 and each conf_cat_id will have same conf_values (same as t_int_act.frst_mrch_id) but actv_flg might be different (set to N for 12 and Y for 13). Need to fetch only active ones
3. t_cas_alt_nmnt will have cast_ids that are enrolled to receive certain mails if enrl_flg is Y for these. Not all cast_ids will have record in this table.
When a cast_id is enrolled by customer service, a record will get inserted with src_id = 2.
4. Requirement is to enroll new cast_ids created with frst_mrch_id matching t_cnf.conf_value where conf_cat_id in (12,13)
Match criteira:
If t_int_act_cas.cast_id exists in t_cas_alt_nmnt and have enrl_flg = 'Y' for cas_alt_id = 2 then
insert record with same cast_id, enrl_flg = 'Y' and css_alt_id = 3
If t_int_act_cas.cast_id exists in t_cas_alt_nmnt and have enrl_flg = 'Y' for cas_alt_id = 3 then
insert record with same cast_id, enrl_flg = 'Y' and css_alt_id = 2
If t_int_act_cas.cast_id exists in t_cas_alt_nmnt and have enrl_flg = 'N' for cas_alt_id in (2,3) and src_id = 2 then
Ignore this record.
if t_int_act_cas.cast_id not exists in t_cas_alt_nmnt then
insert 1 record each with cast_id, enrl_flg = 'Y' for css_alt_id 2 and 3
Hope above explanation makes sense.
By the way I tried below sql. Yet to test it for all use cases but it worked for the last two.
Note on PE_OR_PD column. I am just using this column to write separate inserts for css_alt_id 2 and 3.
select
     cast_id,
     upd_date,
     pe_or_pd
from    
     (select
                iac.cast_id                        cast_id,
                sysdate                            upd_date,
                case
                    when c.conf_cat_id = 12 and can.cas_alt_id in (2,3) and enrl_flg = 'Y' then null
                    when c.conf_cat_id = 13 and can.cas_alt_id in (2,3) and enrl_flg = 'Y' then null
                    when c.conf_cat_id = 12 and nvl(can.cas_alt_id,2) = 2 and nvl(can.enrl_flg,'Y') = 'N' and can.src_id <> 2 then 'PE'
                    when c.conf_cat_id = 13 and nvl(can.cas_alt_id,3) = 3 and nvl(can.enrl_flg,'Y') = 'N' and can.src_id <> 2 then 'PD'       
                    when c.conf_cat_id = 12 and nvl(can.cas_alt_id,2) = 2 and nvl(can.enrl_flg,'Y') = 'Y' then 'PE'                                                                     
                    when c.conf_cat_id = 13 and nvl(can.cas_alt_id,3) = 3 and nvl(can.enrl_flg,'Y') = 'Y' then 'PD'                                                          
                end
                    pe_or_pd              
            from
                t_cnf              c,   
                t_int_act          ia,      
                t_intl_act_cus     iac,
                t_cas_alt_nmnt     can              
            where
                c.conf_value               = ia.frst_mrch_id               and
                ia.internal_account_id     = iac.int_act_id                and 
                can.cast_id(+)             = iac.cast_id                   and                               
                c.conf_cat_id              in (12,13)                      and
                c.actv_flg                 = 'Y'                           and
                -- Fetch all new customer created after last run.   
                ia.create_date             >= trunc(sysdate) - 1                                                                     
     ) enrl_cust
where
    pe_or_pd is not null               
                ;