So at my work we inspect tires, and I'm building a sheet to input each day's inspections so that I can see a monthly view.

I have a query in cell A7 in my "Monthly Report" sheet/tab that works, but it breaks with Unable to parse query string for Function QUERY parameter 2: AVG_SUM_ONLY_NUMERIC if one of the columns in the query doesn't contain any numerical values amongst their rows.

My query is =QUERY({'1st'!A7:D;'2nd'!A7:D}, "SELECT Col1, SUM(Col2), SUM(Col3), SUM(Col4) GROUP BY Col1")

I've read from a similar post I should be using the n() function but haven't been able to get the syntax to work. I'm really pushing my limits on google sheet knowledge so any education/help would be lovely.

A simplified copy of the sheet is below.

Output: