我有一个包含以下信息聚合函数
date sales
2011-02-13 1
2011-02-13 3
2011-02-13 2
2011-02-14 1
2011-02-14 5
2011-02-14 8
2011-02-15 2
etc ...
我怎么知道什么是周期平均量的表? 比如我要得到这样一个结果: 销售2,4为每天期间2011-02-11 - 2011-02-15
我有一个包含以下信息聚合函数
date sales
2011-02-13 1
2011-02-13 3
2011-02-13 2
2011-02-14 1
2011-02-14 5
2011-02-14 8
2011-02-15 2
etc ...
我怎么知道什么是周期平均量的表? 比如我要得到这样一个结果: 销售2,4为每天期间2011-02-11 - 2011-02-15
select avg(sales) from table where date <= x and date >= y
您的X和Y的日期如
select avg(sales) from table where date <= '2011-02-15' and date >= '2011-02-11'
如果`date`
是DATE
数据类型:
SELECT SUM(sales)/(1 + DATEDIFF('2011-02-15', '2011-02-11'))
AS AverageSalesPerDay
FROM TableX
WHERE `date` BETWEEN '2011-02-11'
AND '2011-02-15'
如果是DATETIME
或TIMESTAMP
:
SELECT SUM(sales)/(DATEDIFF('2011-02-16', '2011-02-11'))
AS AverageSalesPerDay
FROM TableX
WHERE `date` >= '2011-02-11'
AND `date` < '2011-02-16'
你从哪儿弄来2,4? – SAN