conditional concatenate?

[richard1029]

Hello, newbie here.

I want to concatenate cells A1 and A2 if B1 and B2 is duplicate. I tried using IF function but I don't know how to make it work for more than 2 rows. For example, see the attached image.

Screenshot 2020-10-29 035321.png

[AliGW]

Please share the solution.

[richard1029]

Here's the solution:

First, add a header row. Then use the formula below

=IF(B2<>B1,A2,C1&A2)

It is not exactly the same as what I want but it works.

Attachment 701775