Multiplying values of same PKs - sql

Question

I have the following table:
+-----+------+
| qwe | asdd |
+-----+------+
| a | 3 |
| a | 4 |
| b | 5 |
| b | 6 |
+-----+------+
The result should be something like this:
+-----+------+
| qwe | asdd |
+-----+------+
| a | 12 |
| b | 30 |
+-----+------+
I wrote a code that may be only applied to the actual table, but if we add a row or more, it is not working well:
select qwe, (SUM(asd) - MIN(asd)) * MIN(asd) a from t
group by qwe
How would you recommend me to modify this code to make it work properly with tables like this?
+-----+------+
| qwe | asdd |
+-----+------+
| a | 3 |
| b | 4 |
| b | 5 |
| a | 6 |
| a | 7 |
+-----+------+
And get table like this:
+-----+------+
| qwe | asdd |
+-----+------+
| a | 12 |
| b | 126 |
+-----+------+

Answer 1

There is no built in PRODUCT() function. Alas.
Assuming all your values are positive, you can do:
select qwe, exp(sum(log(asdd))) as aggregate_product
from t
group by qwe;
Note: This can be extended to handle 0 and negative values. That just adds a lot of extra stuff to the expression, which hides the fundamental logic.
To prevent problems with zero:
select qwe, coalesce(exp(sum(log(nullif(asdd, 0)))), 0) as aggregate_product
Negative numbers are a bit trickier.