如何合并同年不同月份的行以获得总数量？

Question

有没有办法可以将同一年内列中的所有日期合并为一行，以便我知道该年度不同列中产品的总数量？

Answer 1

使用Group_Concat或Group by

Select Group_Concat(col_name) From table Group by Year(date)

或

Select Group_Concat(col_name) From table 
where Year(date)='2015' Group by Year(date)

Answer 2

使用YEAR()功能：

SELECT YEAR(someDate) AS year, SUM(qty) AS `total quantity`
FROM someTable
WHERE product='some product'
GROUP BY YEAR(someDate)