Inner join request to get the items available for the user - postgresql

Question

I have four tables:
CREATE TABLE t_users (
user_id varchar PRIMARY KEY,
user_email varchar
);
CREATE TABLE t_items (
item_id varchar PRIMARY KEY,
owner_id varchar not null references t_users(user_id),
title varchar
);
CREATE TABLE t_access_gropes (
access_group_id varchar PRIMARY KEY,
user_id varchar not null references t_users(user_id)
);
CREATE TABLE t_access_sets (
access_set_id varchar PRIMARY KEY,
item_id varchar not null references t_items(item_id),
access_group_id varchar not null references t_access_gropes(access_group_id)
);
With data:
INSERT INTO t_users VALUES ('us123', 'us123#email.com');
INSERT INTO t_users VALUES ('us456', 'us456#email.com');
INSERT INTO t_users VALUES ('us789', 'us789#email.com');
INSERT INTO t_items VALUES ('it123', 'us123', 'title1');
INSERT INTO t_items VALUES ('it456', 'us456', 'title2');
INSERT INTO t_items VALUES ('it678', 'us789', 'title3');
INSERT INTO t_items VALUES ('it323', 'us123', 'title4');
INSERT INTO t_items VALUES ('it764', 'us456', 'title5');
INSERT INTO t_items VALUES ('it826', 'us789', 'title6');
INSERT INTO t_items VALUES ('it568', 'us123', 'title7');
INSERT INTO t_items VALUES ('it038', 'us456', 'title8');
INSERT INTO t_items VALUES ('it728', 'us789', 'title9');
INSERT INTO t_access_gropes VALUES ('ag123', 'us123');
INSERT INTO t_access_gropes VALUES ('ag456', 'us456');
INSERT INTO t_access_gropes VALUES ('ag789', 'us789');
INSERT INTO t_access_sets VALUES ('as123', 'it123', 'ag123');
INSERT INTO t_access_sets VALUES ('as456', 'it456', 'ag123');
The t_access_gropes forms groups of users.
The t_access_sets forms security kits.
How to make a request to get the all items available for the user. Something like:
select *
from t_items
inner join t_users on t_items.owner_id = t_users.user_id
inner join t_access_gropes on t_users.user_id = t_access_gropes.user_id
inner join t_access_sets on t_items.item_id = t_access_sets.item_id
where t_access_gropes.user_id = 'us123';
Thank you.

Answer 1

select u.user_id, u.email, i.item_id, i.title
from t_users u
join t_items i on i.owner_id = u.user_id
where u.user_id = 'us123'
I believe this is what you want for your exact request!
Otherwise what you wrote is fine however I dont see the relevance in the tables you joined together as you directly connected your users table and items table together, which is why you wouldnt need to join the other two tables (groups & sets). Usually in some cases you find a table of user_items inbetween the users and items table.