You can now document the cells in a query. However, this topic is relevant for BW/4HANA. A document is identified by the name of the key figure and the filter for this key figure, which affects the cell in the query. The text length of a document is unlimited. You can assign a document to a hierarchy node or a subtotal. You can also assign a document to restricted and calculated key figures. To make it possible to add comments for calculated key figures, you have to assign a technical ID. Make sure that these are unique. Documents can be reused in other queries if the filter selection is identical. A document is therefore visible in all queries that contain the same cell. You can even find documents from the drilldown in the selection and vice versa, as long as their common part is identical.
3155931 - Comments is not showing cross queries with same granularity of data
2980332 - Collective note for the BW Document Store
SAP Online Documentation
An introduction and overview to this topic is available in the following link:
help.sap.com: Creating a Document Store
Creating a Document Store
First of all, we start with creating a document store object. For the required InfoArea of the project area choose
The Document Store maintenance screen appears. On the General tab, the system displays the technical name and the description. To assign the document store to InfoProviders, switch to the InfoProvider tab and choose Add.
6. By clicking on wrench symbol(1), you can display further information on document store object. "Show Document" button (2) on the menu, shows the already added comments.
7. Now the document store object is created. Next prerequisite is to maintain the query properties.
Choose the query > select the tab "Runtime Properties" (step1) > turn on the Document Support (step2) > assign your document store (step3)