I'm having problems understanding NULL. I grasp what a NULL value is,
but I can't get NULL to perform correctly. For instance, if I do a
Select statement, I see that I have columns with a NULL value.
select first, last, suffix from persons LIMIT 5;
+-----------+----------+--------+
| first | last | suffix |
+-----------+----------+--------+
| Benjamin | Page | NULL |
| Jonathan | Watson | NULL |
| Jose | Thorson | NULL |
| Alejandro | Nickels | NULL |
| Griselda | Richards | NULL |
+-----------+----------+--------+
5 rows in set (0.01 sec)
Logically, it seems that a Select statement should find these five plus
any other NULL values in the suffix column. However, such a select
statment returns an empty set.
mysql> select first, last, suffix from persons where suffix IS NULL;
Empty set (0.00 sec)
Does anyone see what I'm doing wrong? (Thanks in advance for any help.)
