Average values with specific parameters

Question

In Google Sheets I have data in the range Sheet3!A:C as pictured below:

I would like to average the values in "Volume (ml)" (range Sheet3!C:C), by unique combination of "ID Primary" and "Date".

Below is an example of my expected output based on the sample data above.

Answer 1

Alternate Formula:

Based on your given data, this formula uses Query and Substitute to convert the volume data from comma-separated to period-separated decimal and display the average volume per ID and Date

=SORT(ARRAYFORMULA(QUERY({Sheet1!A:B, IFERROR(VALUE(SUBSTITUTE(Sheet1!C:C, ",", ".")))}, "SELECT Col1, Col2, AVG(Col3) WHERE Col1 IS NOT NULL GROUP BY Col1, Col2 LABEL AVG(Col3) 'Average Volume (mL)'",1)), 1, False)

Result:

Note: Please adjust the Sheet name accordingly that suits your google sheets

References:

Query Function

Substitute