将两列按功能SQL分组

Question

如果我有以下选择查询：

select col1, col2, col3, sum(value1) as col4, col5
from table1
group by col1, col2, col3, col5

如何添加col6 = col4 / col5？

Answer 1

您不能在SELECT子句中访问别名。 所以你必须重复sum(value1) ：

select col1, col2, col3, 
       sum(value1) as col4, 
       col5, 
       sum(value1) / col5 as col6
from table1
group by col1, col2, col3, col5

Answer 2

在派生表中执行GROUP BY ：

select col1, col2, col3, col4, col5, col4/col5 as col6 
from
(
    select col1, col2, col3, sum(value1) as col4, col5
    from table1
    group by col1, col2, col3, col5
) dt

Answer 3

您可以在select语句中执行操作。 但是，您不能在其中使用SQL语句的别名。 因此，您需要再次对col4进行计算。 只需将sum(value1)/col5 as col6添加sum(value1)/col5 as col6 。

select col1, col2, col3, sum(value1) as col4, col5, sum(value1)/col5 as col6
from table1
group by col1, col2, col3, col5