> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/build/aggregate.md).

# Aggregate items into one list in Duaer

In Duaer, Aggregate turns many input items into fewer outputs. You can collect selected fields, or pack the whole batch into one list.
## Collect selected fields

1. Search for Aggregate and connect it after the previous node.
2. Set Aggregate to Individual Fields.
3. Under Fields To Aggregate, add an Input Field Name, for example id. Turn on Rename Field when you need a different Output Field Name.
4. Select Execute step. The output is often one item with the collected fields.

All Item Data (Into a Single List) packs every item into one list field. Put Output in Field is that field’s name.
## Questions

### How is Aggregate different from Merge in Duaer?

Aggregate works on many items on one path. Merge waits for several branches, then combines them. Refer to [Merge branches in Duaer](/flow-logic/merging.md).