Table:
0
A
B
C
D
E
1
guest id
gender code
guest first name
guest last name
date of birth
2
1
Male
Kip
DuBuque
1995-11-04 07:09:57
3
2
Unknown
Rebeca
Runolfsdottir
1974-05-12 21:53:58
4
3
Female
Keon
Treutel
1974-08-20 09:28:05
5
4
Female
Gabe
Bode
2007-09-11 19:01:39
6
5
Female
Lou
Grady
1997-01-15 17:37:40
7
6
Unknown
Josefina
Jerde
1978-03-08 04:43:04
8
7
Female
Mozell
Toy
1997-01-20 17:11:31
9
8
Unknown
Keith
Hoeger
2001-06-18 20:05:55
10
9
Female
Crystal
Runolfsson
1971-01-04 04:22:58
11
10
Female
Nikki
Lehner
1980-06-20 18:15:39
12
11
Male
Gregoria
Schowalter
2015-02-03 23:34:13
13
12
Male
Louvenia
Crona
1983-08-26 15:45:08
14
13
Female
Else
Roberts
1971-11-02 01:51:56
15
14
Female
Juvenal
Kautzer
2003-07-29 22:08:15
16
15
Female
Tamia
Mante
2013-02-22 11:26:22

Questions and formulas:
Question: Return the first names and last names of all guests
Formula: CHOOSE({1,2},C1,D1)
Formula2: CHOOSE({1,2},C2:C16,D2:D16)
Level: easy
Question: What are the first names and last names of all the guests?
Formula: CHOOSE({1,2},C1,D1)
Formula2: CHOOSE({1,2},C2:C16,D2:D16)
Level: easy
Question: Return the date of birth for all the guests with gender code "Male".
Formula: FILTER(E1,B1="Male")
Formula2: FILTER(E2:E16,B2:B16="Male")
Level: easy
Question: What are dates of birth of all the guests whose gender is "Male"?
Formula: FILTER(E1,B1="Male")
Formula2: FILTER(E2:E16,B2:B16="Male")
Level: easy
Question: What's the id and full name (first and last name) of every guest?
Formula: UNIQUE(HSTACK(C1,D1,A1))
Formula2: UNIQUE(HSTACK(C2:C16,D2:D16,A2:A16))
Level: easy
Question:  the first name and last name for each guest.
Formula: UNIQUE(HSTACK(C1,D1,A1))
Formula2: UNIQUE(HSTACK(C2:C16,D2:D16,A2:A16))
Level: easy
Question: Birthdays and ids of male guests.
Formula: LET(query1,FILTER(A1:E1,B1="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Formula2: LET(query1,FILTER(A2:E16,B2:B16="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Level: hard
Question: dates of birth and ids of male guests.
Formula: LET(query1,FILTER(A1:E1,B1="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Formula2: LET(query1,FILTER(A2:E16,B2:B16="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Level: hard
Question: What's the id and full name (first and last name) of each guest?
Formula: UNIQUE(HSTACK(C1,D1,A1))
Formula2: UNIQUE(HSTACK(C2:C16,D2:D16,A2:A16))
Level: easy
Question: Dates of birth and ids of the male guests.
Formula: LET(query1,FILTER(A1:E1,B1="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Formula2: LET(query1,FILTER(A2:E16,B2:B16="male"),UNIQUE(CHOOSECOLS(query1,5,1)))
Level: hard