Assuming we have three entries for a drawing:
- entry 1 has a weight of 3
- entry 2 has a weight of 5
- entry 3 has a weight of 2
We want to pick a random winning entry that takes into account the weights. This query will do that.
How do entries get "weights"? Someone enters a drawing which results in an entry being created with a weight of 1. Later that day they are rewarded 5 bonus entries which just translates into us bumping their entry's weight to 6.