Changing a query depending on date

Hi experts, this is a tricky one, at least for a newbie like me. I'm not sure if I should post this question here or in the JavaScript section, I'll let you guys decide. I have three tables, press_schedule, prerun_rpt and publications.

mysql> describe press_schedule;
+------------+-------------+------+-----+---------+----------------+
| Field      | Type        | Null | Key | Default | Extra          |
+------------+-------------+------+-----+---------+----------------+
| press_id   | smallint(6) | NO   | PRI | NULL    | auto_increment |
| press_date | date        | NO   | MUL |         |                |
| pub_id     | smallint(6) | NO   | MUL |         |                |
+------------+-------------+------+-----+---------+----------------+
3 rows in set (0.11 sec)

mysql> describe prerun_rpt;
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| rpt_id      | int(11)      | NO   | PRI | NULL    | auto_increment |
| rpt_date    | date         | NO   |     |         |                |
| pages       | smallint(6)  | YES  |     | NULL    |                |
| sections    | smallint(6)  | YES  |     | NULL    |                |
| pub_id      | smallint(6)  | NO   |     |         |                |

mysql> describe publication;
+----------+--------------+------+-----+---------+-------+
| Field    | Type         | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+-------+
| pub_id   | smallint(6)  | NO   | PRI |         |       |
| pub_name | varchar(100) | NO   |     |         |       |
+----------+--------------+------+-----+---------+-------+
2 rows in set (0.03 sec)

The table press_schedule contains the schedule for the press to run, and the night crew creates a report (prerun_rpt) for each press run that is scheduled. I have created a form for for the prerun_rpt table. It contains a calendar from where the user selects a date, and a drop down box with all the publications from where the user can pick up a publication. What I would like to do, is narrow down the amount of publications depending on the date contained in press_schedule.

Let say that press_schedule has the following information:

mysql> select * from press_schedule;
+----------+------------+--------+
| press_id | press_date | pub_id |
+----------+------------+--------+
|        1 | 2006-09-10 |  10200 |
|        2 | 2006-09-10 |  10201 |
|        3 | 2006-09-10 |  10202 |
|        4 | 2006-09-11 |  10201 |
|        5 | 2006-09-12 |  10202 |
+----------+------------+--------+
5 rows in set (0.00 sec)

And that publication has the following:

mysql> select * from publication;
+--------+----------------------------------+
| pub_id | pub_name                         |
+--------+----------------------------------+
|  10200 | TV Week                          |
|  10201 | Best Bets                        |
|  10202 | Lyon County Tab 01520000         |

When the user creates a report for '2006-09-10', only three choices will be shown in the drop down box, 'TV Week', 'Best Bets' and 'Lyon County Tab 01520000'. If the user chooses '2006-09-11', only one option will show, 'Best Bets'. How can I accomplish this? I'm using PHP and MySQL. Thanks!