通过联接表从数据库中选择数据

Question

I'm currently making a website that is used to advertise car sharing for festivals. I need to list all trips which are currently assigned to a user but seeing as the database relationship would be many to many I have had to make a client_trip table.

My question:
How would I select trips from the trip table based on the information in my client_trip table?

I'm currently using PostgreSQL and Java servlets. Thanks very much for any help. :)

CREATE TABLE users
(
user_id SERIAL,
user_username VARCHAR (20),
user_firstname VARCHAR(20),
user_surname VARCHAR(20),
user_password VARCHAR(50),
user_email VARCHAR(100),
user_role VARCHAR(20),
PRIMARY KEY(user_id)
);

CREATE TABLE trips
(
trip_id SERIAL,
trip_name VARCHAR (100),
trip_user_username VARCHAR (50),
trip_festival_id SERIAL REFERENCES festivals(festival_id),
trip_festival_name VARCHAR(100),
trip_depart_date DATE,
trip_return_date DATE,
trip_spaces INT,
trip_cost Decimal (19,2),
trip_desc VARCHAR,
PRIMARY KEY(trip_id)
);

Answer 1

how would I select trips from the trip table based on the information in my client_trip

With a given user_id :

SELECT t.*
FROM   trips t
JOIN   client_trip ct USING (trip_id)
WHERE  ct.user_id = ??