Table:
0
A
B
C
D
E
F
1
customer id
payment method
customer name
customer phone
customer email
date became customer
2
1
Visa
Ron Emard
1-382-503-5179x53639
shaniya45@example.net
4/25/2011 22:20
3
2
MasterCard
Gabe Schroeder
1-728-537-4293x0885
alexandra91@example.net
10/17/2011 16:08
4
3
Discover
Candace Schneider
940.575.3682x7959
tkassulke@example.com
1/11/2012 21:17
5
4
Visa
Jaden Lang
361.151.3489x7272
dedric17@example.org
12/29/2009 17:38
6
5
Visa
Geovanni Grady
1-005-644-2495
elmira.langworth@example.org
5/21/2017 7:09
7
6
Visa
Dr. Karine Farrell
+49(2)0677806107
reichel.winnifred@example.org
11/6/2010 8:42
8
7
Discover
Emmanuel Reilly
129.959.6420
gleichner.ethelyn@example.net
11/29/2013 6:15
9
8
MasterCard
Keenan Kuhic
686-517-9923x348
dallin76@example.org
4/9/2013 18:17
10
9
American
Rusty Morar
1-123-197-9677x7194
njenkins@example.org
9/9/2015 9:29
11
10
Visa
Lila Howe
1-492-284-1097
leann.hamill@example.org
2/4/2014 4:51
12
11
Visa
Amalia Hudson DDS
003-991-1506x483
danika49@example.com
2/25/2014 19:39
13
12
Discover
Verda Streich
6730471330
xgraham@example.org
10/12/2008 12:19
14
13
Discover
Patience Yundt
969-208-8932x715
kira82@example.com
3/25/2017 18:48
15
14
Visa
Annabell Walsh
(881)096-1281x6448
adriana83@example.org
6/30/2017 19:02
16
15
Visa
Aracely Borer V
531-617-3230
rollin95@example.net
9/13/2015 22:39

Questions and formulas:
Question: Find the number of customers in total.
Formula: SUM(A1)
Formula2: SUM(A2:A16)
Level: easy
Question: How many different payment methods are there?
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B16))
Level: easy
Question: List the names and emails of customers who payed by Visa card.
Formula: CHOOSE({1,2},FILTER(E1,B1="Visa"),FILTER(C1,B1="Visa"))
Formula2: CHOOSE({1,2},FILTER(E2:E16,B2:B16="Visa"),FILTER(C2:C16,B2:B16="Visa"))
Level: medium
Question: List the names, phone numbers, and emails sorted by the dates of becoming customer
Formula: SORT(UNIQUE(HSTACK(C1,D1,E1,F1)), 4, 1)
Formula2: SORT(UNIQUE(HSTACK(C2:C16,D2:D16,E2:E16,F2:F16)), 4, 1)
Level: medium
Question: the count of payment methods
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B16))
Level: easy
Question: visa customers names and emails
Formula: LET(query1,FILTER(A1:F1,B1="visa"),UNIQUE(CHOOSECOLS(query1,3,5)))
Formula2: LET(query1,FILTER(A2:F16,B2:B16="visa"),UNIQUE(CHOOSECOLS(query1,3,5)))
Level: hard
Question: the date, phone, name and email of customer from earliest to latest
Formula: SORT(UNIQUE(HSTACK(F1,D1,C1,E1)), 1, 1)
Formula2: SORT(UNIQUE(HSTACK(F2:F16,D2:D16,C2:C16,E2:E16)), 1, 1)
Level: medium
Question: the names and emails of customers who pay by visa
Formula: LET(query1,FILTER(A1:F1,B1="visa"),UNIQUE(CHOOSECOLS(query1,3,5)))
Formula2: LET(query1,FILTER(A2:F16,B2:B16="visa"),UNIQUE(CHOOSECOLS(query1,3,5)))
Level: hard