Công thức cho C2:
=IFERROR(TRIM(LEFT(SUBSTITUTE(INDEX($A$2:$A$19,AGGREGATE(15,6,ROW($A$1:$A$19)/(COUNTIF($C$1:C1,LEFT($A$2:$A$19,FIND("_",$A$2:$A$19)-1))=0),ROW(A1))),"_",REPT(" ",100)),100)),"")
Công thức cho D2:
=AGGREGATE(14,6,--SUBSTITUTE($A$2:$A$19,C2&"_",""),1)