Google Sheets - how to get the first and the last value? - google-sheets

Question

Thank you for your time!
I am trying to make a trade journal in Google Spreadsheets.
What I want is the entry price and exit price of the trades,
Which are cell C10 and cell C11 in the screenshot image below.
I just manually typed the correct value - 960 and 2200.
Fortunately, the entry price for C10 is always what's in cell H2,
Because the first input will always be "Buy" in column F.
However I'm stuck finding the exit value.
I want it to find the last non-zero value of column H, only when column F contains "Sell".
What formula can I write?
enter image description here

Answer 1

You can do it with a combination of
INDEX
QUERY
COUNTA
Query for entries in column H where F is equal to "sell" and H is not 0.
From the retrieved subset of data, get the one with the last index (by counting the total amount of indices with COUNTA).
Sample formula:
=INDEX(
QUERY(F2:H, "select H where (F = 'sell' and H <> 0)"),
COUNTA(
QUERY(F2:H, "select H where (F = 'sell' and H <> 0)")
),
1
)

Answer 2

You can also do it without QUERY() (even though it is a really cool function).
=INDEX(H:H,MAX(IF((F:F="Sell")*H:H,ROW(F:F)),-1))
Find last row number where "Sell" appears in Column F and the corresponding value in Column H is non-zero. Since the row number monotonically increases, MAX() always gives us the last occurrence. If the row says "Buy" instead, or the value is 0, then IF() returns -1. We cannot use 0 because INDEX() evidently returns the whole range if we do that.
Use that row number as an index for column H to get the corresponding value. If no valid value was found, we get a #NUM error, which you can handle with IFERROR() if you'd like.
Note: we can't use a VLOOKUP() and approximate match because Action is unsorted.