Analyze Bill Lengths

For all penguins in the little_penguins table, get the species, island, beak length, average beak length in the table, and the difference in beak length for each penguin from the average. Build a result table with the fields species, island, bill_length_mm, avg_bill_length_mm, diff_from_avg_bill_length_mm.
Solve the problem using window functions.