As the title say, if i have a table with 3 rows, and i want to add a flag to the first two rows that meet a condition, how can i do that in M code?
| Invoice ID | Type | Weight | Destination | Sale ID |
| A32 | Invoice | 10 | F | 1 |
| A14 | Credit note | -10 | F | 1 |
| A33 | Invoice | 10 | D | 1 |
In this example I have a list of invoices with different details and values (this is just an mock up example, can't post the real table). Sometimes due to a mistake while completing an invoice they have to cancell the invoice creating a credit note. See example: first row is the created invoice with destination F, but the correct destination was D, so they first create a credit note that cancells the invoice, and then they create an invoice with the correct destination. Notice how the credit note has a negative numeric value to indicate it's cancelling the first one.
What I want to do is create a custom column using M code in power query that flags the first two rows so that i can then know which inoices have been cancelled, and then flags the third row which is the one that's correct.
| Invoice ID | Type | Weight | Destination | Sale ID | Flag |
| A32 | Invoice | 10 | F | 1 | N |
| A14 | Credit note | -10 | F | 1 | N |
| A33 | Invoice | 10 | D | 1 | Y |
Also I would like to add a Y flag if there's only one apparence of the row, meaning there was no cancellation asociated with that sale ID.
