I have the following situation. In Column (C2) I have no data if Column (C1) has an B, otherwise there is always data. Therefore my tables looks like this:

C1 C2

A 2

A 3

A 6

B ?

B ?

A 3

B ?

What I need is a solution to copy the previous row in the next row, as long as there are Bs in Column (C1). The result should look like this:

you have two possibilities. The first one is to use a Java Snippet and save the previous value in variable.

The second one is as follows: Use a lag column node, to get a new column with the previous value for each row. Use a Rule Engine, to replace the missings for B. You can also check for missing in the Rule Engine node.