When you set up backup, save, or export email messages into Google Sheets you might want to improve your Google spreadsheet so it also has a number of messages in a Gmail conversation.
This can be easily done using a very powerful Google Sheets QUERY formula.
To do that just add the following query as the last column of the spreadsheet:
=QUERY(A2:B, "select A, count(B) where B != '' group by A label A 'Thread Id', count(B) 'Number of emails messages in a thread'", 0)
Explanation
The first parameter of the formula is A2:B. This will select all cells from A and B columns starting with the second row (the first rows is a header). The thread Ids are in column A while message ids are in column B.
The second parameter is the actual query:
- The clause group by A tells the query to group everything by value of A.
- The select count(B) tells the query to display number of messages which have the same thread Id
- The label part of the query tells the query which text to display in headers
Example
The example Google Sheet which the above is here