### Database Schema:
CREATE TABLE trains (
	id	INTEGER	NOT NULL	PRIMARY KEY,
	direction	TEXT	NULL	DEFAULT NULL
);

CREATE TABLE cars (
	id	INTEGER	NOT NULL	PRIMARY KEY,
	train_id	INTEGER	NULL	DEFAULT NULL,
	position	INTEGER	NULL	DEFAULT NULL,
	shape	TEXT	NULL	DEFAULT NULL,
	len	TEXT	NULL	DEFAULT NULL,
	sides	TEXT	NULL	DEFAULT NULL,
	roof	TEXT	NULL	DEFAULT NULL,
	wheels	INTEGER	NULL	DEFAULT NULL,
	load_shape	TEXT	NULL	DEFAULT NULL,
	load_num	INTEGER	NULL	DEFAULT NULL,
	foreign key (train_id) references trains (id)
);

### User's Query:
Please list the IDs of all the cars on train no.1 that have 2 wheels.

### Extra Knowledge:
train no.1 refers to train_id = 1; 2 wheels refers to wheels = 2
SELECT id FROM cars WHERE train_id = 1 AND wheels = 2