如何计算计算列的平均值

Question

I have data in a table called transaction, I have derived purchase value ie final_rat1 * quantity and sum of purchase quantity

Buysell     Quantity    Final_rat1 
B           50          88.14
B           230         88.14
B           75          88.14
B           87          88.14
B           187         88.14
B           150         88.14
B           221         88.14

Below is the code for it, but when I am averaging purchase value / sum of purchase quantity I'm unable to get proper average. Could you please guide me on this. Below is the code, which I have mentioned

sum(case
        when sauda.buysell = 'B' then
            sauda.quantity * 1
        else
            0
        end) as "P.Qty",
sum(case
        when sauda.buysell = 'B' then
            sauda.quantity * (sauda.final_rat1 + sauda.brokpercontract)
        else
            0
        end) As "P.value",
sum(case
        when sauda.buysell = 'B' then
            sauda.quantity * (sauda.final_rat1 + sauda.brokpercontract)/sauda.quantity
        else
            0
        end) as "P.Avg"

Actual Average should be 88.14 where as im getting an average of 616.98 and if i remove the sum from below average query

case
    when sauda.buysell = 'B' then
        sauda.quantity * (sauda.final_rat1 + sauda.brokpercontract)/sauda.quantity
    else
        0
    end as "P.Avg"

it says "not a group by function"

Answer 1

Perhaps you mean something like this:

sum(case
    when sauda.buysell = 'B' then
        sauda.quantity * 1
    else
        0
    end) as "P.Qty",
sum(case
    when sauda.buysell = 'B' then
        sauda.quantity * (sauda.final_rat1 + sauda.brokpercontract)
    else
        0
    end) As "P.value",
avg(case
    when sauda.buysell = 'B' then
        sauda.final_rat1 + sauda.brokpercontract
    else
        0
    end) as "P.Avg"