They might look similar but these two aggregations answer different questions COUNT(*) returns the number of rows produced by the query It counts every row, regardless of whether any column contains ...

SQL COUNT() is the #1 screening question for data roles. ⚠️ Get it wrong = automatic rejection. Your next interview depends on these. Including NULLs COUNT(*) / COUNT(1) → counts all rows 🚫 Excluding ...

COUNT_BIG(*) returns the number of items in a group. This includes NULL values and duplicates. COUNT_BIG (ALL expression) evaluates expression for each row in a group, and returns the number of ...