Answer the questions below by developing queries in SQL. Please input queries in SQL to make sure they answer the questions.

1. Which suppliers did not deliver any items in September?

2. Which employees did not sell any items in June?

3. What was the percentage of sales value by merchandise category in March?

AdoptionGroup AdoptionID ContactName Animal Animalld Name Category Breed Dateom Gender Registered Color Photo ImageFile Imageheight ImageWidth AdoptionllD SalelD ContactPhone Breed Category Breed City EmployeelD Supplier LastName CitylD ZIPCode City State AreaCode Population1990 Population1980 Country Latitude Longitude Category Registration FirstName Phone Address Name ContactName Phone CitylD TaxPayerlD DateHired DateReleased Sale ZIPCode CitylD Customer Salel Managerlb Employeelevel Title SaleDate EmployeelD CustomerlD SalesTax CustomerlD Phone FirstName LastName Address ZIPCode CitylD MerchandiseOrder OrderDate ReceiveDate SupplierlD EmployeelD ShippingCost Orderltem PONumber ItemiD Quantity Cost ItemID Description QuantityOnHand Saleltem SalelD ItemiD Quantity SalePrice Category