Transformation & aggregation — flashcards
One card per lesson — 4 in this module. Recall the key points, then check. 4 cards. Click a card to flip, or use the arrow keys and space bar.
The Joiner node — what are the key points?
Tick output combinations to build inner, left, right or full outer · Split output gives matched and unmatched tables separately · GroupBy the right branch first to prevent row multiplication Read the lesson
Concatenate and Column Appender — what are the key points?
Concatenate matches columns by name; choose union or intersection · Duplicate RowIDs cause failures — let the node generate new ones · Column Appender matches by position, not by key — misaligns silently Read the lesson
The GroupBy node — what are the key points?
Columns neither grouped nor aggregated are silently dropped · Set naming to Keep original names or downstream references break · Moving Aggregation is the window-function equivalent and needs sorting first Read the lesson
Pivoting and Unpivoting — what are the key points?
Unpivoting turns value columns into rows — usually the first step · Pivoting generates column names from data, so the schema changes with the data · Use pattern-based selection downstream of a pivot Read the lesson