SQL字段不同值数量统计

SELECT
	customer_id,
	count(*) num
FROM
	uic_contract
GROUP BY
	customer_id 
ORDER BY
	num desc

SELECT
	uea.energy_id,
	uep.prod_name,
	sum( uea.cost_num ) num
FROM
	uic_energy_account uea
	LEFT JOIN uic_energy_prod uep ON uep.id = uea.energy_id
WHERE
	uea.is_deleted = 0
GROUP BY
	uea.energy_id