Question

I have had mysql query to check any particular reservations existing in database . These conditions are working in patient doctor reservation system

Background :
I have system which checks available time slots .And displays next available time . As per system my next available time is 9:15 AM to 10:45 AM . But there in admin side I’ve set a reservation 10:00AM to 10:30,this is set by admin . So I need to show users a message “There is a booking between the requested time 9:15 to 10:45 .You can’t use the entire time” .

I wrote a query but its not working ,its not giving any results

SELECT * 
FROM reservation
WHERE facility_id =  '24'
AND (
'2012-03-02 09:15:00' >= CONCAT( reservation_date,  ' ', reservation_time,  ':00' ) 
AND  '2012-03-02 09:15:00' <= CONCAT( reservation_date,  ' ', reservation_end_time,  ':00' )
)
AND  '2012-03-02 10:45:00' >= ( CONCAT( reservation_date,  ' ', reservation_time,  ':00' ) 
AND  '2012-03-02 10:45:00' <= CONCAT( reservation_date,  ' ', reservation_end_time,  ':00' ) ) 

Anyone can tell me any problem with my query .

Answer 1

It shouldn’t work becouse you are comparing strings not datetime values. use for example Date_FORMAT() like this:

SELECT * 
FROM reservation
WHERE facility_id =  '24'
AND (
 DATE_FORMAT('2012-03-02 09:15:00' , "%Y-%m-%d %H:%i:%s") 
 >= 
 DATE_FORMAT(CONCAT( reservation_date,  ' ', reservation_time,  ':00' ), "%Y-%m-%d %H:%i:%s") 
AND  
...

BTW: This is a bad design, it would be be easier if reservation_date is a datetime, then you can directly compare the two values using BETWEEN or without all these casting.