PostgreSQL querying through schemas - postgresql

Question

I want a query that lists all Customers who's status is "active". This query would return a list of customers who are marked as active. My problem is that I am lost on querying tables that reference other tables. Here is my schema.
CREATE TABLE Customer (
ID BIGSERIAL PRIMARY KEY NOT NULL,
fNAME TEXT NOT NULL,
lNAME TEXT NOT NULL,
create_date DATE NOT NULL DEFAULT NOW()
);
CREATE TABLE CustomerStatus (
recordID BIGSERIAL NOT NULL,
ID BIGSERIAL REFERENCES Customer NOT NULL,
status TEXT NOT NULL,
create_date DATE NOT NULL DEFAULT NOW()
);
INSERT INTO Customer (fNAME, lNAME) VALUES ('MARK', 'JOHNSON'), ('ERICK', 'DAWN'), ('MAY', 'ERICKSON'), ('JESS', 'MARTIN');
INSERT INTO CustomerStatus (ID, status) VALUES (1, 'pending'), (1, 'active');
INSERT INTO CustomerStatus (ID, status) VALUES (2, 'pending'), (2, 'active'), (2, 'cancelled');
INSERT INTO CustomerStatus (ID, status) VALUES (3, 'pending'), (3, 'active');
INSERT INTO CustomerStatus (ID, status) VALUES (4, 'pending');

Answer 1

I took courage to assume that record_id is serial => the latest id would be the last, to produce this qry:
t=# with a as (
select *, max(recordid) over (partition by cs.id)
from Customer c
join CustomerStatus cs on cs.id = c.id
)
select *
from a
where recordid=max and status = 'active';
id | fname | lname | create_date | recordid | id | status | create_date | max
----+-------+----------+-------------+----------+----+--------+-------------+-----
1 | MARK | JOHNSON | 2017-04-27 | 2 | 1 | active | 2017-04-27 | 2
3 | MAY | ERICKSON | 2017-04-27 | 7 | 3 | active | 2017-04-27 | 7
(2 rows)
Time: 0.450 ms