Summing values across multiple spreadsheets based on date - google-sheets

Question

I'm trying to sum values across multiple Google Sheet spreadsheets (workbooks) that are grouped by dates. For example, I want to sum all the Delta values for March 2, 2020 across multiple spreadsheets and each spreadsheet will have 0 or more values for that date.
Here's an example with 2 spreadsheets:
Spreadsheet 1:
Date Start Stop Delta
Mon 02Mar20 16:51 16:56 0:05
Mon 02Mar20 16:56 17:00 0:03
Tue 03Mar20 18:45 18:49 0:03
Tue 03Mar20 19:04 19:06 0:01
Spreadsheet 2:
Date Start Stop Delta
Mon 02Mar20 8:38 8:49 0:11
Tue 03Mar20 4:47 4:50 0:03
Tue 03Mar20 17:42 17:55 0:13
Tue 03Mar20 17:58 18:45 0:47
Tue 03Mar20 18:53 19:03 0:10
I want to have a dynamic sum of the Delta columns across spreadsheets by each day in a separate spreadsheet. So here's what I would like to autogenerate. Specifically, the sum of the Delta values for Spreadsheet 1 and Spreadsheet 2 for each day (0:08, 0:11, 0:04, 1:10):
Date Total Spreadsheet 1 Spreadsheet 2
Mon 02Mar20 0:19 0:08 0:11
Tue 03Mar20 1:14 0:04 1:10
I tried using IMPORTRANGE but I'm not sure how to make the sums dynamic for each day. I don't know ahead of time how many entries I'll have for each date in Spreadsheet 1 and 2 so I want to have a way to auto determine how many rows to sum up each day for Spreadsheet 1 and 2. I'm guessing I would need to use QUERY or FILTER to filter all the imported values from IMPORTRANGE but I'm not sure how to do that.

Answer 1

I made an easy dataset to be sum up. Got a Spreadsheet like this:
As you can see, the total sum values for 2nd march would be 2 and for 3rd March would be 20.
In a different Spreadsheet, got my dashboard:
The formula I've used in B2 is:
=SUMPRODUCT(--(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1rnap9LJQJaqriiJLSsF7EWQLwBUiNviktxDAMFfW0ZE";"Hoja 1!A1:A4")=$A2);IMPORTRANGE("https://docs.google.com/spreadsheets/d/1rnap9LJQJaqriiJLSsF7EWQLwBUiNviktxDAMFfW0ZE";"Hoja 1!B1:B4"))
This is how it works:
--(IMPORTRANGE("https://docs.google.com/spreadsheets/d/1rnap9LJQJaqriiJLSsF7EWQLwBUiNviktxDAMFfW0ZE";"Hoja 1!A1:A4")=$A2) will compare the values of column A in Workbook 1 with the date in column A in my main dashboard. Because we've used a double unary operator this will return an array of 1 and 0 if there is a match or not (in this case, it will be an array like {1;1;0;0}
IMPORTRANGE("https://docs.google.com/spreadsheets/d/1rnap9LJQJaqriiJLSsF7EWQLwBUiNviktxDAMFfW0ZE";"Hoja 1!B1:B4") will return as array the values of column B in Workbook 1, in this case it will return {1;1;10;10}
SUMPRODUCT will multiply both arrays and sum up the values, in this case {1;1;0;0} * {1;1;10;10} = {1;1;0;0} and the sum up of this final array is 2.
Same logic applied to second date, we would obtain {0;0;1;1} * {1;1;10;10} = {0;0;10;10} -> 20
Just add each workbook in 1 different column with same formula, and then do a normal sum up in your main dashboard to get the Grand total sum for all values in all workbooks for a specific date:
Hope this helps.
NOTICE: Of course, this method will work only if your dates are dates (not strings/texts) and the times in Delta are date/times too (not strings/texts)