In most counting scenarios in Excel, COUNTBLANK reliably counts blank cells, and COUNTA reliably counts populated cells. However, with these functions comes a problematic paradox: an empty string from ...
SharePains by Pieter Veenstra on MSN

CountRows, CountIf, CountA and Count in Power Apps

How often would you like to count the number of records without really wanting to load all the records that exist in a list ...