Вариант

G_Z 04.07.2014 16:13

SELECT
	c.car_id,
	c.date,
	c.car_name,
	c.car_modification,
	c.price,
	c.mileage,
	c.color,
	i.img_name
FROM (
	SELECT
		car_id,
		MIN(img_id) AS img_id
	FROM images
	GROUP BY car_id
	ORDER BY NULL
)           AS ci
JOIN cars   AS c ON (c.car_id = ci.car_id)
JOIN images AS i ON (i.img_id = ci.img_id)

Но без схемы и данных сложно сказать, что будет лучше.

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