Table:
0
A
B
C
D
E
F
1
game id
id
player
injury
number of matches
source
2
1
1
Davide Santon
Clean-up surgery on his right knee
12
inter.it
3
2
2
Maicon
Knee problem
2
inter.it
4
3
3
Dejan Stanković
Hamstring muscle strain in his left thigh
2
inter.it
5
4
4
Wesley Sneijder
Foot injury
1
inter.it
6
5
5
Diego Milito
Slight thigh strain in right leg
1
inter.it
7
5
6
Javier Zanetti
Post-traumatic pneumothrorax
4
inter.it
8
6
7
Walter Samuel
Right thigh muscle strain
3
inter.it
9
6
8
Thiago Motta
Surgery on his right knee
10
inter.it
10
6
9
Goran Pandev
Ankle problem
3
inter.it
11
8
10
Iván Córdoba
Sustained a biceps femoris strain in his left leg
1
inter.it
12
9
11
Esteban Cambiasso
First-degree strain left hamstring muscles
2
inter.it
13
10
12
Dejan Stanković (2)
Right calf strain
4 (6)
inter.it
14
10
13
Wesley Sneijder (2)
Fainted during half time
1 (2)
inter.it
15
11
14
Esteban Cambiasso (2)
Sustained posterior thigh strains in his left leg
4 (6)
inter.it
16
12
15
Thiago Motta (2)
Knee problem
7 (17)
inter.it

Questions and formulas:
Question: How many different kinds of information sources are there for injury accidents?
Formula: ROWS(UNIQUE(F1))
Formula2: ROWS(UNIQUE(F2:F16))
Level: easy
Question: total number of sources for each injury
Formula: SUMMARIZE(D1,DCOUNTX(F1))
Formula2: SUMMARIZE(D2:D16,DCOUNTX(F2:F16))
Level: easy
Question: the number of matches for each source and player who doesn't injure because of a knee problem.
Formula: LET(query1,FILTER(A1:F1,D1<>"knee problem"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,6,3)),SUMX(CHOOSECOLS(query1,5))))
Formula2: LET(query1,FILTER(A2:F16,D2:D16<>"knee problem"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,6,3)),SUMX(CHOOSECOLS(query1,5))))
Level: hard
Question: the number of sources for each injury
Formula: SUMMARIZE(D1,DCOUNTX(F1))
Formula2: SUMMARIZE(D2:D16,DCOUNTX(F2:F16))
Level: easy