在MYSQL中的表中选择同一行中三个连续值的总和

Question

请参阅表格以提供sql查询以获得类似的结果。

ggplot(df2, aes(x = DateYM, y=Qty))

期望的输出：

id value
1  10
2  15
3  30
4  10
5  11
6  12

http://sqlfiddle.com/#!9/21cbc8

Answer 1

将ID除以3，将其四舍五入，将其分组（使用sum）：

SELECT 
    ceiling(id / 3) AS NewID, 
    sum(Value)      AS SumValue
FROM MyTable
GROUP BY ceiling(id / 3)

使用变量：

SET @GroupVar = 3;  -- Set this number to whatever you want to group by

SELECT 
    ceiling(id / @GroupVar) AS NewID, 
    sum(Value)      AS SumValue
FROM MyTable
GROUP BY ceiling(id / @GroupVar);