I need the SQL Query for these, I keep receiving errors.

1. How many PG rating movies mention of in their description?

Display: number of movies

2. How many customers using store 1 have first name Kelly? (Hint: Customer using store 1 has store_id =1)

Display: number of customers

3. For different film ratings (i.e., G, PG, R, NC-17), which film rating has the highest average rental rate?

Display: highest rating and its average rental rate

4. Return the first five unique first name of customers which starts with a letter S based on alphabetical order.

Display: first name