<select id="statGoods" resultType="map">
select
substr(add_time,1, 10) as day,
count(distinct order_id) as orders,
sum(number) as products,
sum(number*price) as amount
from litemall_order_goods
group by substr(add_time,1, 10)
</select>
group by substr(add_time,1, 10)——以add_time的前10个字符进行分组后查询
这里的意思是将在表litemall_order_goods里进行查询,并将查询结果生成四列进行显示,分别是:day、orders、products、amount