Table:
0
A
B
C
D
E
F
1
people id
nationality
name
birth date
height
2
1
Russia
Aleksey Ostapenko
May 26, 1986
207.0
3
2
Bulgaria
Teodor Salparov
August 16, 1982
182.0
4
3
Russia
Roman Bragin
April 17, 1987
187.0
5
4
Russia
Sergey Grankin
January 22, 1987
193.0
6
5
Russia
Yevgeni Sivozhelez
August 8, 1986
196.0
7
6
Russia
Maksim Botin
July 14, 1983
194.0
8
7
Russia
Semen Poltavskiy
February 8, 1981
205.0

Questions and formulas:
Question: What are different nationalities of people and the corresponding number of people from each nation?
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: How many people are there of each nationality?
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: Give the nationality that is most common across all people.
Formula: LET(a,HSTACK(B1,A1),b,A1,c,CHOOSECOLS(TAKE(SORT(SUMMARIZE(A1,COUNTX(A1)), 2, -1), 1),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Formula2: LET(a,HSTACK(B2:B8,A2:A8),b,A2:A8,c,CHOOSECOLS(TAKE(SORT(SUMMARIZE(A2:A8,COUNTX(A2:A8)), 2, -1), 1),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Level: hard
Question: What are the nationalities that are shared by at least two people?
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Formula2: LET(query1,SUMMARIZE(B2:B8,SUMX(A2:A8)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Level: hard
Question: Return the nationalities for which there are two or more people.
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Formula2: LET(query1,SUMMARIZE(B2:B8,SUMX(A2:A8)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Level: hard
Question: List the names and birth dates of people in ascending alphabetical order of name.
Formula: SORTBY(CHOOSE({1,2},C1,D1),C1,1)
Formula2: SORTBY(CHOOSE({1,2},C2:C8,D2:D8),C2:C8,1)
Level: easy
Question: What are the names and birth dates of people, ordered by their names in alphabetical order?
Formula: SORTBY(CHOOSE({1,2},C1,D1),C1,1)
Formula2: SORTBY(CHOOSE({1,2},C2:C8,D2:D8),C2:C8,1)
Level: easy
Question: Show names of people whose nationality is not "Russia".
Formula: FILTER(C1,B1<>"Russia")
Formula2: FILTER(C2:C8,B2:B8<>"Russia")
Level: easy
Question: What are the names of people who are not from Russia?
Formula: FILTER(C1,B1<>"Russia")
Formula2: FILTER(C2:C8,B2:B8<>"Russia")
Level: easy
Question: How many distinct nationalities are there?
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy
Question: Count the number of different nationalities.
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy
Question: How many people from each country? 
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: Total people from each country
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: Which nationality is most common?
Formula: TAKE(SORT(SUMMARIZE(B1,COUNTX(B1)), 2, -1), 1)
Formula2: TAKE(SORT(SUMMARIZE(B2:B8,COUNTX(B2:B8)), 2, -1), 1)
Level: hard
Question: The nationalities shared by at least 2 people.
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Formula2: LET(query1,SUMMARIZE(B2:B8,SUMX(A2:A8)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Level: hard
Question: Which nationalities are there at least two people for? 
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Formula2: LET(query1,SUMMARIZE(B2:B8,SUMX(A2:A8)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Level: hard
Question: People's names in alphabetical order and their corresponding dates of birth 
Formula: SORT(UNIQUE(HSTACK(C1,D1,A1)), 1, 1)
Formula2: SORT(UNIQUE(HSTACK(C2:C8,D2:D8,A2:A8)), 1, 1)
Level: medium
Question: The names of people from 'a' to 'z' and their corresponding birthdays
Formula: SORT(UNIQUE(HSTACK(C1,D1,A1)), 1, 1)
Formula2: SORT(UNIQUE(HSTACK(C2:C8,D2:D8,A2:A8)), 1, 1)
Level: medium
Question: All names and IDs, excluding people from Russia
Formula: LET(query1,FILTER(A1:F1,B1<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Formula2: LET(query1,FILTER(A2:F8,B2:B8<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Level: hard
Question: The names and people ids of those not from Russia.
Formula: LET(query1,FILTER(A1:F1,B1<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Formula2: LET(query1,FILTER(A2:F8,B2:B8<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Level: hard
Question: Total recorded nationalities
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy
Question: How many nationalities are there?
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy
Question: How many people do we have of each nationality?
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: The number of people of each nationality.
Formula: SUMMARIZE(B1,SUMX(A1))
Formula2: SUMMARIZE(B2:B8,SUMX(A2:A8))
Level: easy
Question: The nationality which at least 2 people have in common.
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Formula2: LET(query1,SUMMARIZE(B2:B8,SUMX(A2:A8)),FILTER(query1,CHOOSECOLS(query1,3)>=2))
Level: hard
Question: What are the names of people from 'a' to 'z' and their corresponding dates of birth?
Formula: SORT(UNIQUE(HSTACK(C1,D1,A1)), 1, 1)
Formula2: SORT(UNIQUE(HSTACK(C2:C8,D2:D8,A2:A8)), 1, 1)
Level: medium
Question: What are the names and people ids of those not from Russia?
Formula: LET(query1,FILTER(A1:F1,B1<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Formula2: LET(query1,FILTER(A2:F8,B2:B8<>"russia"),UNIQUE(CHOOSECOLS(query1,3,1)))
Level: hard
Question: The number of nationalities.
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy
Question: How many nationalities?
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B8))
Level: easy