Strange MySQL behavior, or not?

[Eric B]

I don't believe I've ever had the occasion to come across the behavior in the third query before. Is this normal? Is MySQL essentially trying to evaluate the integer value of the field if the query doesn't include quotes around the zero?

mysql> DESC listing_elective;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| listing_id | int(11)      | NO   | PRI |         |       |
| elective   | varchar(20)  | NO   | PRI |         |       |
| value      | varchar(100) | NO   |     |         |       |
+------------+--------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> SELECT * FROM listing_elective;
+------------+----------------+--------------+
| listing_id | elective       | value        |
+------------+----------------+--------------+
| 21         | contact_name   | Earl Jones   |
| 26         | employees      | 65           |
...
| 31         | employees      | 12           |
| 31         | contact_value  | 800-555-1212 |
+------------+----------------+--------------+
59 rows in set (0.01 sec)

mysql> SELECT * FROM listing_elective WHERE `value` IN (0);
+------------+--------------+--------------+
| listing_id | elective     | value        |
+------------+--------------+--------------+
| 21         | contact_name | Earl Jones   |
+------------+--------------+--------------+
1 rows in set (0.01 sec)