Question

I’m trying to run a MYSQL query where I need the same ‘piece’ of information from the source table twice in the destination…
Let me explain:

2 Tables: “Events” and “Archived Events“.
The “Archived Events” is a ‘link’ – bridging current open events to past (closed) events.
This table only contains id’s to the Event_ID in the Events table.

What I want to do is get the Event Title for each combination in the archive table.

EG:

   -----------------------------------
   |       ARCHIVE TABLE             |
   |PK|ClosedEventID |CurrentEventID |
   |1 |      5       |       3       |
   |2 |      2       |       3       |
   -----------------------------------

   -----------------------------------------
   |      EVENTS TABLE                     |
   |Event_ID | Event_Title | ............. |
   |    1    | Party 1     | ............. |
   |    2    | Party 2     | ............. |
   |    3    | Wedding 1   | ............. |
   |    4    | Funeral 1   | ............. |
   |    5    | Pancake     | ............. |
   ----------------------------------------

I’m guessing it’s going to be a join or a union or something; my SQL is fair, but my head is spinning trying to work this out.

So what I would like done is that for each ‘pair’ in the archive events table would look like this once the query was run (so that I can deal with it in PHP…):

   -----------------------------------
   |       ARCHIVE TABLE             |
   |PK|ClosedEventID |CurrentEventID |
   |1 | Pancake      |   Wedding 1   |
   |2 | Party 2      |   Wedding 1   |
   -----------------------------------

Thank you for your help in advance! 🙂

Answer 1

This is fairly simple:

SELECT
    a.pk as "pk",
    e1.event_title as "closed_event",
    e2.event_title as "current_event"
FROM
    events as e1
    JOIN archive as a on e1.event_id = a.closed_event_id
    JOIN events as e2 on a.current_event_id = e2.event_id