Louis Davidson can easily get to 20:
I was reading LinkedIn posts the other day when I saw this blog about what was apparently an interview question about some forms of a COUNT aggregate function
This was apparently asked in an interview. What will each of these constructs do in a SQL statement:
COUNT(*) = ?COUNT(1) = ?COUNT(-1) = ?COUNT(column) = ?COUNT(NULL) = ?COUNT() = ?
There’s one tricky bit in this set. Louis then takes it a bit further with CASE expressions and variables, so check out the post for the answers as well as those additional examples in T-SQL.