Only write sql queries ASAP

Question 5:

Show the number of customers assigned to each of the employees.

Question 6:

From the invoices, show which country's customers spent the most on the tracks.

Question 7:

Show the top 3 artists based on their track sales.

Question 8:

Show the track name names, album name, artist name and genre of all the artist whose names contains last letter from your artist name.

Artist Album Track 3-00 00 Artistid Name Albumid Title Artistid Media Type A MediaTypeid Name Genre 3-001 Trackid Name Albumid MediaTypeid Genreid Composer Milliseconds CO Bytes UnitPrice Playlist 00 -3-00 PlaylistTrack Playlistid Trackid Genreld Name 7 Playlistid Name InvoiceLine InvoiceLineid Invoiceld TrackId UnitPrice Quantity Customer Invoice Employee Employeeld LastName FirstName Title ReportsTo BirthDate HireDate Address City State Country PostalCode Phone Fax Email 300 Customerid FirstName LastName Company Address City State Country PostalCode Phone Fax Email SupportRepid Invoiceld Customerid InvoiceDate BillingAddress Billing City BillingState Billing Country BillingPostalCode Total -0-00