I hope my question dosn´t asked in the past.
Is it possible to remove rows with double entry attributs (only one row of this should remain)?
If yes: Is there any possibility to remove rows in relationship with attribus in other colums in same row.
Yes, you will be able to perform this kind of operation as soon as 1.3 is released which is going to happen very soon. Please stay tuned.
Regarding your questions, there will be a GroupBy node which allows you to group columns by certain attribute values and at the same time performs an aggregation on all other columns. Furthermore, we will have a Column Comparator node which compares two values within the same row and then appends the result within a new column. This column can then be used to filter out all rows (Row Filter node) for which the condition does not hold.