Postgres 15

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CREATE TABLE users (
    id serial NOT NULL,
    firstname varchar(64) NOT NULL,
    lastname varchar(64) NOT NULL,
    kid integer NOT NULL
);

CREATE TABLE keys (
    id serial NOT NULL,
    key varchar(1024) NOT NULL,
    tid integer NOT NULL
);

CREATE TABLE terminals (
    id serial NOT NULL,
    name varchar(64),
    ipaddr integer NOT NULL
);

CREATE TABLE

CREATE TABLE

CREATE TABLE

INSERT INTO users (firstname, lastname, kid) VALUES ('jas', 'wedrowniczek', 1);
INSERT INTO users (firstname, lastname, kid) VALUES ('mariusz', 'kolano', 2);
INSERT INTO users (firstname, lastname, kid) VALUES ('ziobro', 'zbigniew', 3);
INSERT INTO users (firstname, lastname, kid) VALUES ('kornel', 'makuszynski', 4);
INSERT INTO users (firstname, lastname, kid) VALUES ('henryk', 'sienkiewicz', 5);

INSERT INTO keys (key, tid) VALUES ('key1', 1);
INSERT INTO keys (key, tid) VALUES ('key2', 2);
INSERT INTO keys (key, tid) VALUES ('key3', 3);
INSERT INTO keys (key, tid) VALUES ('key4', 4);
INSERT INTO keys (key, tid) VALUES ('key4', 5);

INSERT INTO terminals (name, ipaddr) VALUES ('pokoj1', 180879367);
INSERT INTO terminals (name, ipaddr) VALUES ('pokoj2', 180879468);
INSERT INTO terminals (name, ipaddr) VALUES ('pokoj3', 288704395);
INSERT INTO terminals (name, ipaddr) VALUES (null, 288703396);
INSERT INTO terminals (name, ipaddr) VALUES ('pokoj5', 0);

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

INSERT 0 1

select *
from users;
select *
from keys;
select *
from terminals;

id
firstname
lastname
kid

1
jas
wedrowniczek
1

2
mariusz
kolano
2

3
ziobro
zbigniew
3

4
kornel
makuszynski
4

5
henryk
sienkiewicz
5

SELECT 5

id
key
tid

1
key1
1

2
key2
2

3
key3
3

4
key4
4

5
key4
5

SELECT 5

id
name
ipaddr

1
pokoj1
180879367

2
pokoj2
180879468

3
pokoj3
288704395

4
null
288703396

5
pokoj5
0

SELECT 5

with t as (
select *
from   terminals 
where  ipaddr = 0 
   or  name is null 
)

select u.id 
      ,u.firstname 
      ,u.lastname   
      ,t.ipaddr   
      ,t.name    
from   users u join keys k using(id) join t on k.tid = t.id

id
firstname
lastname
ipaddr
name

4
kornel
makuszynski
288703396
null

5
henryk
sienkiewicz
0
pokoj5

SELECT 2

id	firstname	lastname	kid
1	jas	wedrowniczek	1
2	mariusz	kolano	2
3	ziobro	zbigniew	3
4	kornel	makuszynski	4
5	henryk	sienkiewicz	5

id	name	ipaddr
1	pokoj1	180879367
2	pokoj2	180879468
3	pokoj3	288704395
4	null	288703396
5	pokoj5	0