Question

我有一个包含以下字段的表：

season, collection, product_key, units_sold

我想添加额外的

cumulative_sold column(aggreate of previous rows values)

应满足order by season, collection,units_sold

sample input
---------- 
ss,f1,1,3
ss,f1,2,4
ss,f1,3,4
ss,f2,1,1
ss,f2,5,1

expected output 
--------------
ss,f1,1,3,3 
ss,f1,2,4,7(3+4)
ss,f1,3,4,11(3+4+4)
ss,f2,1,1,1
ss,f2,5,1,2(1+1)

Answer 1

您可以使用相关子查询执行累计求和：

select season, collection, product_key, units_sold,
       (select sum(units_sold)
        from t t2
        where t2.season < t.season or
              t2.season = t.season and t2.collection < t.collection or
              t2.season = t.season and t2.collection = t.collection and t2.units_sold <= t.units_sold
       ) as cumsum            
from t;

这是标准的SQL。如果您有大量数据，则需要t(season, collection, units_sold)上的索引。

编辑：

如果您只希望在特定季节中使用此特定集合，而不是总体累积总和：

select season, collection, product_key, units_sold,
       (select sum(units_sold)
        from t t2
        where t2.season = t.season and t2.collection = t.collection and
              t2.units_sold <= t.units_sold
       ) as cumsum            
from t;

编辑II：

这是一种非常标准的SQL类型。如果你能得到正确的问题会有所帮助。处理units_sold上的重复项：

select season, collection, product_key, units_sold,
       (select sum(units_sold)
        from t t2
        where t2.season = t.season and t2.collection = t.collection and
              (t2.units_sold < t.units_sold or
               t2.units_sold = t.units_sold and t2.product_key <= t.product_key
              )
       ) as cumsum            
from t;

每行mysql的列的聚合值

1 个答案: