Last QTY based on selected date

[ChristianDGreat]

Hello would it be okay if you can help me on this? I got stucked

So I have this table

Product	Timestamp	Qty
A	1-Jan	23
A	2-Jan	123
A	3-Jan	123
A	4-Jan	213
B	1-Jan	123
B	2-Jan	123
B	4-Jan	123
C	1-Jan	10
C	2-Jan	11
C	4-Jan	13

and the result that im looking for is this
Filter Timestamp = 1/3

Product	Last Qty
A	123
B	123
C	11

Explanation : So what I'm looking for is I want to get the latest qty by Product depending on what I filter.
So If I filter 1/3/2023 it will only scan below or equal to that date.
A = 123 from 1/3/2023

B = 123 from 1/2/2023

C = 11 from 1/2/2023

[johnt75]

You can create a measure like

Qty as at date =
VAR MaxDate =
    MAX ( 'Date'[Date] )
VAR Qty =
    SELECTCOLUMNS (
        CALCULATETABLE (
            TOPN ( 1, 'Table', 'Table'[Timestamp], DESC ),
            'Date'[Date] <= MaxDate
        ),
        "@qty", 'Table'[Qty]
    )
RETURN
    Qty

[ChristianDGreat]

@johnt75 thanks, but when I add my full table it seems its only working if we are only looking at one column (product)
Anyway

What if this is the table, I added a subtype

Product	Timestamp	Subtype	Qty
A	1-Jan	A-1	23
A	2-Jan	A-1	123
A	3-Jan	A-2	123
A	4-Jan	A-2	213
B	1-Jan	B-1	123
B	2-Jan	B-1	123
B	4-Jan	B-2	123
C	1-Jan	C-1	10
C	2-Jan	C-1	11
C	4-Jan	C-3	13

This is the error I got.

The result im looking for is 

Product	Qty	explanation
A	246	A-1 (jan 2) = 123	A-2 (jan3) = 123	Total = 246
B	123	B-1(jan 2) = 123		Total = 123
C	11	C-1(jan2) = 11		Total = 11

Let me know if it makes sense.

[johnt75 · Accepted solution]

Try

Qty as at date =
VAR MaxDate =
    MAX ( 'Date'[Date] )
VAR SummaryTable =
    ADDCOLUMNS (
        SUMMARIZE ( 'Table', 'Table'[Product], 'Table'[Subtype] ),
        "@qty",
            SELECTCOLUMNS (
                CALCULATETABLE (
                    TOPN ( 1, 'Table', 'Table'[Timestamp], DESC ),
                    'Date'[Date] <= MaxDate
                ),
                "@qty", 'Table'[Qty]
            )
    )
RETURN
    SUMX ( SummaryTable, [@qty] )