Using database function please answer the questions

Purchases
Date	Description	Vendor	Total	Employee
1/1/2008	printer paper	Papermart	300	Sue
1/16/2008	books	Borders	250	Mary
1/31/2008	envelopes	OfficeMax	375	Tom
2/15/2008	legal paper	OfficeMax	300	Dave
3/1/2008	letter paper	OfficeMax	400	Gary
3/16/2008	bond paper	OfficeMax	400	Sue
3/31/2008	tape	Staples	25	Mary
4/15/2008	folders	Staples	25	Tom
4/30/2008	pencils #1	Staples	10	Dave
5/15/2008	pencils #2	Staples	10	Gary
5/30/2008	computer model # 123	Dell	2000	Sue
6/14/2008	computer model # 234	Dell	2200	Mary
6/29/2008	computer model # 345	Dell	1800	Tom
7/14/2008	pens black	Papermart	50	Dave
7/29/2008	pens blue	Papermart	50	Gary
8/13/2008	pens red	Papermart	25	Sue
8/28/2008	disks	Staples	100	Mary
9/12/2008	books	Borders	25	Tom
9/27/2008	books	OfficeMax	35	Dave
10/12/2008	printer	Best Buy	245	Gary
1	Total amount of purchases from Dell
2	Total amount of purchases from OfficeMax
3	Total amount of purchases from Papermart
4	Total amount of purchases from Staples
5	Count the number of purchases placed by Tom
6	Count the number of purchases from Staples
7	Total amount of purchases for pens and pencils
8	Total amount of purchases for books from Borders
9	Total amount of purchases that took place in July
10	Average amount spent on computers
11	Total amount spent on black and blue pens
12	Total amount spent at Staples during March
13	Total amount of purchases that Mary placed
14	Total amount of computer purchases ordered by Sue
15	Count the number of purchases that took place after April 1