情况：
产品表、库存表两张表关联查询，由于一个产品有多个库存记录，需查出最新的库存记录
解决方案：
SELECT
a.hotel_id \'酒店ID\',
a.ticket_product_id \'产品ID\',
a.sell_date_start \'销售开始时间\',
a.sell_date_stop \'销售结束时间\',
a.sale_price \'售价\',
t.init_count \'总库存\',
t.day_limit_count \'每日限量库存\'
FROM
ticket_product a
LEFT JOIN (
SELECT
b.*
FROM
product_inventory b
LEFT JOIN ( SELECT max( c.product_inventory_id ) AS product_inventory_id, c.product_id FROM product_inventory c GROUP BY c.product_id ) d ON b.product_inventory_id = d.product_inventory_id
) t ON a.ticket_product_id = t.product_id