Get rows product (multiplication)

Question

SO,

The problem

I have an issue with rows multiplication. In SQL, there is a SUM() function which calculates sum for some field

Answer 1

I guess this would work...

SELECT IF(MOD(COUNT(data < 0),2)=1
        , EXP(SUM(LOG(data)))*-1
        , EXP(SUM(LOG(data))))
          x 
  FROM my_table;