Q. Why are NULL values ignored when using the MAX or MIN function?
A. A NULL value means that nothing is there, so there would be no maximum or minimum value.
Q. Why don’t data types matter when using the COUNT function?
A. The COUNT function counts only rows.
Q. Does the data type matter when using the SUM or AVG function?
A. Not exactly. If the data can be implicitly converted to numeric data, then it will still work. It’s less a function of what the data type is and more about what data is stored in it.
Q. Are you limited to using only column names inside of aggregate functions?
A. No, you can use any type of calculation or formula as long as the output corresponds to the proper type of data that the function is expecting to use.