What is wrong with the following query?

Select timeslotID,duration from timeslot where timeslot.timeslotID NOT IN (Select timeslotstatus.timeslotID from timeslotstatus where date='2004-02-19' and equipmentID=1);

The tables used are:
timeslot & timeslotstatus


The version being used is My SQL 4.0.1 on Windows.

The following are the create table statements of the two tables :---

DROP TABLE IF EXISTS `timeSlot`;
CREATE TABLE `timeSlot` (
`timeSlotID` varchar(20) NOT NULL default '',
`startTime` datetime NOT NULL default '0000-00-00 00:00:00',
`endTime` datetime NOT NULL default '0000-00-00 00:00:00',
`dayOfWeek` int NOT NULL default 0,
`duration` int(11) NOT NULL default 0,
`companyID` varchar(20) NOT NULL default '',
PRIMARY KEY (`timeSlotID`)
) TYPE=InnoDB;

DROP TABLE IF EXISTS `timeSlotStatus`;
CREATE TABLE `timeslotstatus` (
`appointmentID` varchar(20) NOT NULL default '',
`timeSlotID` varchar(20) NOT NULL default '',
`patientID` varchar(20) NOT NULL default '',
`staffID` varchar(20) NOT NULL default '',
`equipmentID` varchar(20) NOT NULL default '',
`providerID` varchar(20) NOT NULL default '',
`date` date NOT NULL default '0000-00-00',
`status` char(1) NOT NULL default 'A',
`companyID` varchar(20) NOT NULL default ''
) TYPE=InnoDB;


The following is the select statement that I recd from dbforums.

SELECT
`timeslot`.`timeSlotID`,
`timeslot`.`duration`
FROM
`timeslot`,
`timeslotstatus`
WHERE
(`timeslotstatus`.`equipmentID` = 1) AND
(`timeslotstatus`.`date` = '2004-02-19') AND
(`timeslot`.`timeSlotID` NOT IN (`timeslotstatus`.`timeSlotID`))


This is not returning the desired results. What I require is that a selct query to be inside the not in clause.

As an example, the statement select timeslotID from timeslot would produce the following ids:--

1
2
3
4
5



whereas the outer select would produce suppose only the following:---

2
4
5



Hence, the output that I require is the ids not present in timslot.

1
3


This is my objective.

see this thread