Problems with Group Loop and Excel Writer setup
Hi all, I’m building a KNIME workflow that reads all .xlsx files in a folder, loops all sheets per file, processes each sheet, concatenates the results, and then writes one Excel workbook with one sheet per vehicle-part category (e.g., Front, KVKL, Seite, HSP etc.).
I’m using two Excel Readers per sheet because each sheet contains two structurally different blocks that I need in parallel: a main matrix (row-wise data) and a small block of auxiliary/meta fields (different header/row offset/column range). A single reader/config can’t reliably pull both at once, so I read the same sheet twice with different settings and then merge the results so the meta fields are attached to every data row.
Current wiring: two Excel Readers → Joiner → close the sheet loop with Loop End → map category via Rule Engine (creates
Bereich_final) → Group Loop Start over category to write one workbook (fixed output path, sheet name via flow variable).
Problem: the output only contains a subset of the expected category sheets, and the sheets that do appear have their rows duplicated (~3×).
Attached you can find my Excel input files (no real data) and the workflow. Thanks a lot for any tips!
Lorin