a11=if(a1<0,sum(a2:a10),sum(a1:a10))
=SUMIF(A1:A10,">0")
=if(A1>=0,A1=SUM(A1:A10),A1=SUM(A2:A10))
a11键入:=sumif(a1:a10,"a1>=0")
=IF(A1<0,SUM(A2:A10),SUM(A1:A10))