Relation for Google Sheets
Relation for Excel is about to be ported to Google Sheets.
This sheet has user defined functions to make simple relational algebra.
The fun part: The functions work also on Sheets on iPad.
You can save a copy of the sheet to use the functions
This is work in progress
For the moment, the functions are embedded in the sheet, but it should be later an add-in.
You can copy the sheet from