The syntax to use a criteria can vary if you want to make it depend on another cell.
Here are various examples of using the SUMIF() function in Google Spreadsheets and/or Excel.
Sum cells in column B if column A = 10. =SUMIF(A1:A10,10,B1:B10)
Sum cells in column B if column A = what's in A2. =SUMIF(A1:A10,A2,B1:B10)
Sum cells in column B if column A > 10. =SUMIF(A1:A10,">10",B1:B10) =SUMIF(A1:A10,">"&10,B1:B10) Sum cells in column B if column A > what's in A2. =SUMIF(A1:A10,">"&A2,B1:B10)
