Oracle SQL Join columns on 2 conditions

Question

I tried to search forums for my scenario but could not find anything remotely similar. So here goes my long winded explanation : I have 3 tables - order_fact , session_fact and orderline.

create table order_fact (order_no varchar2(20), order_timestamp date, cookie_id number, session_id number);

insert into order_fact values ('69857-20210329', to_date('29-MAR-2021 10:11:58', 'DD-MON-YYYY HH24:MI:SS'), 827678, 79853421);
insert into order_fact values ('78345-20210411', to_date('11-APR-2021 18:37:07', 'DD-MON-YYYY HH24:MI:SS'), 569834, 84886798);
insert into order_fact values ('79678-20210519', to_date('19-MAY-2021 20:51:34', 'DD-MON-YYYY HH24:MI:SS'), 589623, 89556782);
insert into order_fact values ('78759-20210411', to_date('11-APR-2021 09:46:52', 'DD-MON-YYYY HH24:MI:SS'), 685213, 77549823);

create table session_fact (cookie_id number, session_id number, session_timestamp date, marketing_vendor varchar2(30) , referral_type VARCHAR2(2) );

insert into session_fact values (827678, 79853421, to_date('29-MAR-2021 09:47:36', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (827678, 79853378, to_date('28-MAR-2021 12:47:36', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (827678, 79853313, to_date('24-MAR-2021 13:23:36', 'DD-MON-YYYY HH24:MI:SS'), 'Naaptol', 'S');
insert into session_fact values (827678, 79853254, to_date('23-MAR-2021 14:39:56', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (569834, 84886798, to_date('11-APR-2021 14:41:44', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (569834, 84886735, to_date('10-APR-2021 11:03:44', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (569834, 84886687, to_date('08-APR-2021 17:26:49', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (569834, 84886659, to_date('03-APR-2021 11:03:44', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (569834, 84886497, to_date('01-APR-2021 07:59:08', 'DD-MON-YYYY HH24:MI:SS'), 'Google', 'R');
insert into session_fact values (685213, 77549823, to_date('11-APR-2021 09:07:34', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (685213, 77549786, to_date('09-APR-2021 20:51:34', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (685213, 77549589, to_date('07-APR-2021 14:11:57', 'DD-MON-YYYY HH24:MI:SS'), 'FabShopping', 'D');
insert into session_fact values (685213, 77548356, to_date('03-APR-2021 15:38:42', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (589623, 89556782, to_date('19-MAY-2021 16:46:52', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (589623, 89556512, to_date('18-MAY-2021 09:46:52', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (589623, 89556477, to_date('13-MAY-2021 18:34:29', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');
insert into session_fact values (589623, 89556348, to_date('10-MAY-2021 16:13:49', 'DD-MON-YYYY HH24:MI:SS'), '-1', 'D');

create table orderline (order_no varchar2(20), ol_nbr number, ol_ref varchar2(5));

insert into orderline values ('78345-20210411', 0, '-2');
insert into orderline values ('78345-20210411', 1, 'HV3');
insert into orderline values ('78345-20210411', 2, 'HV3');
insert into orderline values ('78759-20210411', 0, '-2');
insert into orderline values ('78759-20210411', 1, 'PS5');
insert into orderline values ('78759-20210411', 2, 'PS5');
insert into orderline values ('78759-20210411', 3, 'PS5');
insert into orderline values ('79678-20210519', 0, '-2');
insert into orderline values ('79678-20210519', 1, 'NPT');
insert into orderline values ('79678-20210519', 2, 'NPT');
insert into orderline values ('69857-20210329', 0, '-2');
insert into orderline values ('69857-20210329', 1, 'HV3');
insert into orderline values ('69857-20210329', 2, 'HV3');
insert into orderline values ('69857-20210329', 3, 'HV3');

As can be seen from above order_fact and session_fact tables are connected by cookie and session id. The request is to get these columns : ORDER_NO, MARKETING_VENDOR, REFERRAL_TYPE, OL_REF from the above 3 tables.

I have written the JOIN query :

select a.ORDER_NO, b.MARKETING_VENDOR,
b.REFERRAL_TYPE, c.OL_REF 
FROM order_fact a 
INNER JOIN session_fact b
ON (a.cookie_id = b.COOKIE_ID AND 
b.session_timestamp < a.order_timestamp AND 
b.session_timestamp > a.order_timestamp-7)
INNER JOIN orderline c ON 
(a.ORDER_NO = c.ORDER_NO AND c.OL_NBR = 1);

Here is the sticky situation for me :

1. Get the data in session_fact table for a cookie_id in order_fact for timestamp of not more than 7 days before the order_timestamp. For example - order_no 78345-20210411 was placed on 11-APR-2021 18:37:07. Using the cookie id of that order I get all rows in session_fact till 11-APR - 7 days = 4-APR. So 3rd and 1st Apr data cannot be considered. This has been taken care in my query. But I wanted to mention why I had the additional AND clauses in the 1st JOIN ON condition.

2. From the data got in point 1 above do not consider those records where REFERRAL_TYPE = 'D' and MARKETING_VENDOR = '-1'. 'S' and '-1' can be considered and so is 'R' and '-1'. Basically any values can be considered as long as its NOT 'D' and '-1'. And select the record whose timestamp is closest to the order_timestamp in table order_fact. Now this is where it gets tricky - if there are no records of past 7 days where combo of REFERRAL_TYPE and MARKETING_VENDOR is NOT 'D' and '-1' then join the tables order_fact and session_fact on both cookie_id and session_id and fetch the values.

3. Join tables order_fact and orderline ON ORDER_NO and OL_NBR = 1. This also has been taken care in my join query.

So my only problem is getting the JOIN between session_fact and order_fact on the 2 different conditions mentioned in point 2. Can this be done by SQL? The Tech Lead of my team asked me to write a PL/SQL block. I did that because the original request was to add MARKETING_VENDOR, REFERRAL_TYPE, OL_REF columns in order_fact table and get the values from their respective tables. I cannot help but feel this can be done by SQL using CASE. Or am I wrong? If anyone could please help me with this query I will be grateful.

Edit : Adding the result data set

Edit : Any kind soul to help me out? 🙂 I take it it's not possible in a SQL statement.

Answer 1

And select the record whose timestamp is closest to the order_timestamp in table order_fact

From your description looks like you just need Top 1 record by session_timestamp:

with
 step1 as (
   SELECT 
       a.ORDER_NO
      ,a.order_timestamp
      ,c.MARKETING_VENDOR
      ,c.REFERRAL_TYPE
      ,c.session_timestamp
   FROM order_fact a 
   cross apply (
       select *
       from session_fact b
       where a.cookie_id = b.COOKIE_ID 
         and (REFERRAL_TYPE,MARKETING_VENDOR) not in (('D','-1'))
         AND b.session_timestamp < a.order_timestamp 
         --AND b.session_timestamp > a.order_timestamp-7
       order by b.session_timestamp desc
       fetch first 1 rows only
   ) c
)
select
   s.*
  ,o.OL_REF 
FROM 
   step1 s
   JOIN orderline o 
        ON (s.ORDER_NO = o.ORDER_NO AND o.OL_NBR = 1)
;

Result:

ORDER_NO       ORDER_TIMESTAMP     MARKETING_VENDOR REFERRAL_TYPE SESSION_TIMESTAMP   OL_REF
-------------- ------------------- ---------------- ------------- ------------------- ------
78345-20210411 2021-04-11 18:37:07 Google           R             2021-04-01 07:59:08 HV3
78759-20210411 2021-04-11 09:46:52 FabShopping      D             2021-04-07 14:11:57 PS5
69857-20210329 2021-03-29 10:11:58 Naaptol          S             2021-03-24 13:23:36 HV3