FILTER or QUERY in Google Sheets? A decision table, 9 side-by-side formulas, and the traps (mixed data types, case, column letters, empty results) that decide which one to use.
Fix the Google Sheets QUERY error "Unable to parse query string for Function QUERY parameter 2": quotes, cell references, dates, clause order, GROUP BY, Col1 and IMPORTRANGE.
Why IMPORTRANGE shows #REF! "You need to connect these sheets" in Google Sheets, how to click Allow access, and what to do when the button never appears.