我想获取mysql数据库中某个表的某个日期范围内具有最高值的前4行。所以我可以用这个代码行来做,例如:
SELECT MONTH(date) as month, amount from sales where date >='2014-01-01' AND date <='2014-12-31' ORDER BY amount DESC LIMIT 4
但我想添加一个新列,其中包含每个值的百分比,我尝试使用此行:
SELECT MONTH(date) as month, amount, round(amount*100/sum(amount) ,1) as 'percent' from sales where date >='2014-01-01' AND date <='2014-12-31' ORDER BY `amount` DESC LIMIT 4
但它不起作用。我怎么才能得到它?我想要一些帮助。
答案 0 :(得分:1)
这是一种做法。提供原始数据的片段也有帮助。创建sql fiddle有助于实现更多目标!!
select month, amount, round(amount*100/total,1) as percent
from
(
select MONTH(date) as month, amount
from sales
where date >='2014-01-01' AND date <='2014-12-31'
ORDER BY amount DESC LIMIT 4
) c JOIN (
select sum(amount) as total
from sales
where date >='2014-01-01' AND date <='2014-12-31'
) t