When you need to include a NULL value?From now on, if there is a null value in the SQL table as shown in the following table, we have to be careful. Because there is a problem, not a problem. It's even more concerning that it's not considered a problem.IDNUMName142A232B3NULLVSELECT COUNT(*) NAME FROM table; -- result : 3SELECT COUNT(NUM) NAME FROM table; -- result : 2If we look at the table abov..