Table:
0
A
B
C
D
E
F
G
H
1
Perpetrator
Date
Year
Location
Country
Killed
Injured
Additional Notes
2
Kehoe, Andrew Philip , 55
05.18 May 18
1927
Bath Township , MI
U.S.
44
58
Committed suicide
3
Cho, Seung-Hui , 23
04.16 April 16
2007
Blacksburg , VA
U.S.
32
17
Committed suicide
4
Lanza, Adam Peter , 20
12.14 Dec. 14
2012
Newtown , CT
U.S.
27
02 2
Committed suicide
5
Hamilton, Thomas Watt , 43
03.13 March 13
1996
Dunblane
U.K.
17
13 13–15
Committed suicide
6
Steinhäuser, Robert , 19
04.26 April 26
2002
Erfurt
Germany
16
01 1
Committed suicide
7
Hz
03.32
1999.9
Dz
Cz
10.9
09.9
Zz
8
Whitman, Charles Joseph , 25
07.31 July 31 / Aug. 1
1966
Austin , TX
U.S.
15
32
Shot by police Killed an unborn child
9
Kretschmer, Tim , 17
03.11 March 11
2009
Winnenden & Wendlingen
Germany
15
09.13 9–13
Committed suicide
10
Lépine, Marc , 25
12.06 Dec. 6
1989
Montreal , QC
Canada
14
14
Committed suicide
11
Harris, Eric David , 18 Klebold, Dylan Bennet , 17
04.20 April 20
1999
Columbine , CO
U.S.
13
21
Both committed suicide
12
Gadirov, Farda , 28
04.30 April 30
2009
Baku
Azerbaijan
12
13
Committed suicide
13
Mz
04.32
2008.9
Mz
U.Kz
14.9
14.9
Zz
14
Menezes de Oliveira, Wellington , 23
04.07 April 7
2011
Rio de Janeiro
Brazil
12
12
Committed suicide
15
Bai Ningyang , 18
05.08 May 8
2006
Shiguan
China
12
05 5
Sentenced to death
16
Seifert, Walter , 42
06.11 June 11
1964
Volkhoven
West Germany
10
22
Committed suicide
17
Saari, Matti Juhani , 22
09.23 Sep. 23
2008
Kauhajoki
Finland
10
01.3 1–3
Committed suicide
18
Wu Huanming , 47
05.12 May 12
2010
Linchang
China
9
11
Committed suicide

Questions and formulas:
Question: On what Date did the massacre result with 21 Injured?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:H1,G1=21),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:H18,G2:G18=21),2))
Level: medium