Question

Im trying to write a procedure to update two tables but im a little stuck on the syntax.

The tables are named SupportTicketsTbl and tblSupportEvent, the link between these tables is a third table named tblTicketsInEvents.

tblSupportEvent has a list of all events that are in a persons schedule, each event has a start and end time, this procedure runs as a sql job and checks if the current time is greater than an events end time, and if so it updates its status.

Now the syntax for this is easy:

UPDATE 
    tblSupportEvent
SET 
    [status] = 3 
WHERE 
    eventend < CURRENT_TIMESTAMP
AND
    [status] = 1

Now here is my problem, an event is linked to a ticket, so when the event linked to the ticket expires I want to set the tickets assigned to value back to 0.

This SELECT query shows the relationship between the tables:

SELECT 
    *
FROM 
    tblSupportEvent e 
JOIN 
    tblTicketsInEvents tie 
ON 
    e.id = tie.eventID 
JOIN 
    SupportTicketsTbl t 
ON 
    t.TicketID = tie.ticketID 

The way I can think to solve this is to select all expired ticket ids into a table then to do an update on SupportTicketsTbl where the ticket ID is in my table variable, though this seems a bit messy. Is there a better way of doing this with an update statement / joins etc?

Im asking because although I can solve the problem myself, and it would probably perform fast enough id like to know the right way of doing this.

Thanks

Answer 1

I believe that doing it this way will work better than creating a temporary table.

UPDATE SupportTicketsTbl
SET toUpdate = newVal
WHERE
    ticketID IN (
        SELECT id
        FROM tblSupportEvent
        WHERE expiredCondition
    )