Table:
0
A
B
C
D
E
F
G
H
I
1
Result
Date
Race
Venue
Group
Distance
Weight (kg)
Jockey
Winner/2nd
2
Won
28 Aug 2010
Memsie Stakes
Caulfield
G2
1400 m
58.5
S. Arnold
2nd - Whobegotyou
3
Won
18 Sep 2010
Underwood Stakes
Caulfield
G1
1800 m
58
S. Arnold
2nd - Dariana
4
Won
9 Oct 2010
Yalumba Stakes
Caulfield
G1
2000 m
58
S. Arnold
2nd - Alcopop
5
Won
23 Oct 2010
Cox Plate
Moonee Valley
G1
2040 m
57.5
S. Arnold
2nd - Zipping
6
Won
30 Oct 2010
Mackinnon Stakes
Flemington
G1
2000 m
58
S. Arnold
2nd - Descarado

Questions and formulas:
Question: The MacKinnon Stakes races took place on how many venues?
Formula: ROWS(UNIQUE(FILTER(D1, C1="Mackinnon Stakes")))
Formula2: ROWS(UNIQUE(FILTER(D2:D6, C2:C6="Mackinnon Stakes")))
Level: medium