將兩列按功能SQL分組

Question

如果我有以下選擇查詢：

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子句中訪問別名。 所以你必須重復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

在派生表中執行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語句中執行操作。 但是，您不能在其中使用SQL語句的別名。 因此，您需要再次對col4進行計算。 只需將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