Let's say our objective is to get latest one row by a given set of criteria. Means, say a person has multiple products and we want to get latest one product per person. For this what we need to do is partition the data by the required criteria. Here we will partition the data by person_id and product_type ordered by latest org_insert_dt. This will order the result by person and latest product. Then we use row_number() function which will assign unique, sequential integer to each partition in the result set. Which means the latest product for each person will get a 1. And we use a CTE (Common Table Expression), which is temporary named result set to store this relationship. Now if we need latest product per person, then we can query this CTE which is like a temp table and get all row_num = 1. Below is a snippet from a larger query which works like I explained above.

with plan_base as (
    -- PROD_A and PROD_B from product per person per product type by plan
    select
        me.person_id,
        prd.product_typ,
        pc.plan_desc,
        pc.orig_insert_dt,
        pc.owner_sponsor_id as sponsor_id,
        row_number() over (partition by me.person_id, prd.product_typ order by pc.orig_insert_dt desc) as row_num
    from product_cfg pc
--  ...
    join membership me
        on me.product_typ = prd.product_typ
        and me.product_grp_id = pc.product_grp_id
    where 
        pc.owner_sponsor_id = 38265559449
        and prd.product_typ in ('PROD_A', 'PROD_B')
),
plan_data as (
    select
        pd.*,
        case 
            when pd.product_typ='PROD_A' and pd.product_grp_id is not null
                then 0 else 1
        end as is_ai
    from plan_base pd
)  -- for simplifying conditionals
select
    p.last_nm as last_name,
    p.first_nm as first_name,
    p.middle_nm as middle_name,
    pd.product_typ as plan
--  ...    
from 
    sponsor s
    join plan_data pd on pd.sponsor_id = s.id and pd.row_num = 1
    join person p on p.id = pd.person_id
--  ...
where 
    s.id = 38265559449
--  ...