Alert Query required when Gross profit is

Dear Experts,

I need your help on generating one alert query.

Our requirement is when we sell an item which we had purchased is having less than 1% gross profit then it should trigger an alert that Gross Profit is less than 1%.

For example: X item purchased at cost of 10 INR and when we sell that item and if gross profit is less than 1 % then it should trigger an alert.

Item is managed by Serial Number. Where condition is with Sales Invoice Date.

I hope I can get such alert query to resolve this task.

Many thanks in advance.

Thanks,

Harshal Makwana