TEXTSPLIT函数，拆分字符函数

A,A,B,B,C

结果：A,B,C

TEXTSPLIT(A1,",")

按","符号拆分字符

UNIQUE(TEXTSPLIT(A1,","),1)

拆分后用UNIQUE函数去重，第二个参数要填写1

TEXTJOIN(",",1,UNIQUE(TEXTSPLIT(A1,","),1))

再用TEXTJOIN函数组合一下就完成了单元格内字符去重