Might be stupid but I have multiplied 2 fields together and created a temporary field using `AS` function. Need to store value of the temporary field to sum it up. 

```
select branchNo,prodCode, prodQty, prodPrice, prodQty * prodPrice AS totalProfit
from transaction WHERE branchNo = 14;

```

So I need to sum up totalProfit

Any ideas (I'm new to MySQL)?