Hi @wu cong? , thank you for your question.
The function you're looking for is the FILL() function. It fills any missing or null values in the specified column with the most recent non-blank value, as determined by the specified window of rows before and after the blank value.
You can see the function's documentation here
And the solution looks like this:
See that while the original order of the rows changes, the desired output is the same.
- Grouped by ColA+ColB
- Sorted by ColC (Sorting by $sourcerownumber would do the trick as well, but I think it's safer to go with ColC)
- filling all empty\null values in a specified group with the non-empty value that precedes it
I've left the 2nd and 3rd parameters of the FILL() function empty, as they're optional and weren't needed for this operation; feel free to read about them either through the function builder in Trifacta itself or via the documentation I've sent.
I hope this makes sense; please feel free to ask any additional questions.
Thanks,
Amit.