How to aggregate joined column?

[HuifangYeo]

Given the below table with just the ProductId and an array HistoricalPrices:

What is being summed when we do a measures["historicalPrices.SUM"] = tt.agg.sum(historicalPrices["HistoricalPrice"])?

[HuifangYeo]

This is the schema:

[Skyscimitar]

Hi HuiFang,
Since you are aggregating a table column, it is aggregated on all levels by default. I'm assuming that there are mulitple OrderId per ProductId so the value you are getting for historicalPrices.SUM is probably the sum of the historical price for a product over all the OrderId it appears in.
To avoid this, you should use:

tt.agg.sum(tt.agg.single_value(table["historicalPrices"]), scope=tt.OriginScope(l["ProductId"]))

[jackschd]

Thankyou for your answer. This is indeed the intention, and the correct implementation.