This post helps explain how you can use CHILDREFS and TEXTJOIN in formulas for data aggregation. Examples and supplemental information is also provided.
A common use of Spreadsheets is to aggregate data across a changing number of sheets. Each time a new sheet is added, cross-sheet formulas must be manually updated in order to ensure all sheet references are captured in the cross-sheet formula. This manual adjustment and verification is time-consuming and increases the risk for material error.
To solve this, Workiva has added new aggregation capabilities to formulas in Spreadsheets: CHILDREFS & TEXTJOIN.
Advanced: Combining CHILDREFS usages
Advanced: Nesting CHILDREFS formulas
Supplementary info for CHILDREFS