SQL函数之数据分组与透视

这篇文章主要讲解了数据分组和数据透视(类似excel的数据透视表)

文章目录

• • • 1、数据分组 并 汇总
    • 2、数据透视

1、数据分组 并 汇总

• group by with rollup ：不同维度的汇总
• 计算各个城市/各个省份/全部省份的总销售额及店铺数量；原数据如下：
  

select province, city, sum(sales) as sum_sales, count(shop) as shop_num
from shop_sale
GROUP BY province,city 
with ROLLUP

2、数据透视

• 计算每天每区的订单量，数据如下：
  

select deal_date
    ,sum(case when area = 'A区' then 1 else 0 end) as 'A区'
	,sum(case when area = 'B区' then 1 else 0 end) as 'B区'
	,sum(case when area = 'C区' then 1 else 0 end) as 'C区'
from order_info 
GROUP BY deal_date