Table:
0
A
B
C
D
E
F
1
Match
Date
Competition or tour
Ground
Opponent
Score1
2
1
15 September 2008
FA Premier Reserve League South
A
Chelsea Reserves
0 - 2
3
2
30 September 2008
FA Premier Reserve League South
H
West Bromwich Albion Reserves
4 - 3
4
3
7 October 2008
FA Premier Reserve League South
A
Fulham Reserves
1 - 4
5
4
21 October 2008
FA Premier Reserve League South
H
Arsenal Reserves
1 - 0
6
5
3 November 2008
FA Premier Reserve League South
A
Tottenham Reserves
0 - 2
7
6
25 November 2008
FA Premier Reserve League South
H
Portsmouth Reserves
2 - 0

Questions and formulas:
Question: What ground had Portsmouth reserves as an opponent?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,E1="portsmouth reserves"),4))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F7,E2:E7="portsmouth reserves"),4))
Level: medium
Question: What ground had a match smaller than 6 and Chelsea Reserves as the opponent?
Formula: LET(query1,LET(query1,FILTER(A1:F1,E1="chelsea reserves"),SUMMARIZE(CHOOSECOLS(query1,4),SUMX(CHOOSECOLS(query1,1)))),FILTER(query1,CHOOSECOLS(query1,2)<6))
Formula2: LET(query1,LET(query1,FILTER(A2:F7,E2:E7="chelsea reserves"),SUMMARIZE(CHOOSECOLS(query1,4),SUMX(CHOOSECOLS(query1,1)))),FILTER(query1,CHOOSECOLS(query1,2)<6))
Level: hard