a.sql

EXPLAIN (SELECT * FROM ((
		SELECT id, status, 'purchase' AS type,
			user_id, NULL AS to_user_id, amount,
			bonus_amount, NULL AS fee, payment_id,
			type AS sub_type,
			finalized_at, created_at
		FROM purchase WHERE 1 AND created_at < FROM_UNIXTIME(1)) UNION (
		SELECT id, status, 'payment' AS type,
			user_id, to_user_id, amount,
			NULL AS bonus_amount, processing_fee AS FEE,
			NULL AS payment_id,
			type AS sub_type, finalized_at, created_at
		FROM payment WHERE 1 AND created_at < FROM_UNIXTIME(1)) UNION (
		SELECT id, status, 'refund' AS type,
			user_id, NULL AS to_user_id, amount,
			NULL AS bonus_amount, NULL AS fee,
			payment_id,
			NULL AS sub_type, finalized_at, created_at
		FROM refund WHERE 1 AND created_at < FROM_UNIXTIME(1))) previous ORDER BY created_at DESC LIMIT 250 )UNION( SELECT * FROM ((
		SELECT id, status, 'purchase' AS type,
			user_id, NULL AS to_user_id, amount,
			bonus_amount, NULL AS fee, payment_id,
			type AS sub_type,
			finalized_at, created_at
		FROM purchase WHERE 1 AND created_at > FROM_UNIXTIME(1)) UNION (
		SELECT id, status, 'payment' AS type,
			user_id, to_user_id, amount,
			NULL AS bonus_amount, processing_fee AS FEE,
			NULL AS payment_id,
			type AS sub_type, finalized_at, created_at
		FROM payment WHERE 1 AND created_at > FROM_UNIXTIME(1)) UNION (
		SELECT id, status, 'refund' AS type,
			user_id, NULL AS to_user_id, amount,
			NULL AS bonus_amount, NULL AS fee,
			payment_id,
			NULL AS sub_type, finalized_at, created_at
		FROM refund WHERE 1 AND created_at > FROM_UNIXTIME(1))) next ORDER BY created_at ASC LIMIT 250 )ORDER BY created_at DESC