Table:
0
A
B
C
1
transaction type code
transaction type description
reference transaction types
2
SALE
Sale
3
PUR
Purchase

Questions and formulas:
Question: pur transaction descriptions
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:C1,A1="pur"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:C3,A2:A3="pur"),2))
Level: medium
Question: The description of pur transaction.
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:C1,A1="pur"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:C3,A2:A3="pur"),2))
Level: medium