Hi @Vysh27 ,
Apologies on my last response but I think I see what the problem is. This error usually comes up when a calculation is mixing fields that QuickSight is evaluating at different levels. In QuickSight, a calculated field has to be evaluated entirely at one level (row-level or aggregated), and ifelse() doesn’t change that behavior.
In this case, I would assume 'bt_broad_tag’ is being evaluated at the row level, while ’day_1_groups’ is being treated as an aggregated value. Because of that, my previous response will not be a solution as once a field is aggregated, it stays that way wherever it’s referenced.
I would recommend referring to this resource for more explanation on how to properly address this error (Finding solutions for mismatched aggregation errors in Quick Sight calculations - Learn / Technical Articles - Amazon Quick Suite Community). Hope this helps and let me know if you are still running into some problems!