循環字母 找出 (9717)

C2{=LEFT(B2,COUNT(0/FREQUENCY(IFERROR(FIND(LEFT(B2,ROW($1:$8)),MID(B2,ROW($2:$9),9)),""),ROW($1:$8))))

另解=LEFT(B2,MIN(IFERROR(FIND(LEFT(B2,ROW($1:$8)),B2,ROW($2:$9))-1,9)))