MySQL - All from one table, not if in other based on 2 values

HAve a table called Master, with a value called UniqueID.

Have a second table called Actions, where the field called ID is the same as the Master table's UniqueID.  (after a form processes, the UniqueID from Master is inserted into the Action table, along with an int called EventID

I want to include every record from Master, unless the UniqueID field matches the one in Action called ID AND the EventID field is the same as a variable passed by a form.  (it's in CF, I can handle the variable part, just not sure where to put it.)

I have this so far:

Select *
FROM Master a LEFT OUTER JOIN Actions b ON a.UniqueID = b.DealerID
WHERE isnull(`b`.`DealerID`)

But I don't know how to add on the rest.
LVL 1
Rush_2112Asked:
Who is Participating?
 
_agx_Commented:
Hm, the 1st one should give you that.  But maybe I'm misunderstanding. Let's say this is your data:

Master
UniqueID    
10
14
16

Actions
DealerID     | EventID
10              | 2
10              | 3
16              | 1

EDIT:  .. and you're filtering on EventID = 3 ie #yourVariableHere# = 3

The results of the 1st query would be:

        UniqueID
        14                         <--  doesn't exist in Actions at all
        16                         <--  exists in Actions, but NOT with eventID = 3

UniqueID = 10 is excluded because there *is* a matching record in Actions with EventID = 3
0
 
Rush_2112Author Commented:
I should mention that I only want records from Master excluded if they're already in the Actions table AND the EventID matches a variable.  If the UnquieID can be found in the Actions table, but alongside a different EventID, then I still want to see it.

Thanks
0
 
_agx_Commented:
If you always want to list the records from Master - even if there are 0 records for a given "UniqueID" in the actions table, try something like this (not tested)

SELECT  *
FROM     Master a LEFT JOIN Actions b
                      ON  a.UniqueID = b.DealerID
                      AND b.EventID =  <cfqueryparam value="#yourVariableHere#" ... >
<!--- ie when there's DealerID matches but
WHERE b.DealerID IS NULL

Otherwise, try using a NOT EXISTS clause

      SELECT  *
      FROM     Master a INNER JOIN Actions b ON  a.UniqueID = b.DealerID
      WHERE  NOT EXISTS (
                     SELECT c.DealerID
                     FROM    Actions c
                     WHERE  c.DealerID = b.DealerID
                     AND       c.EventID =  <cfqueryparam value="#yourVariableHere#" ... >
       )

*Note, need to fill in the "cfsqltype" in cfqueryparam
0
Cloud Class® Course: SQL Server Core 2016

This course will introduce you to SQL Server Core 2016, as well as teach you about SSMS, data tools, installation, server configuration, using Management Studio, and writing and executing queries.

 
Rush_2112Author Commented:
I think you're close, but when I run it, I only get records from Master IF they already have records in ACTIONS.  I need everything in Master UNLESS the UniqueID appears in Actions and then ONLY if it's in Actions and the Events Variable is met (it's a number like 2)

Thank you for the help so far
0
 
_agx_Commented:
(Please see my updated response). Hopefully the example above will tell you know if we're on the same page or not :) If not, let me know what results you'd like instead (and why)
0
 
Rush_2112Author Commented:
Right but the Master has thousands of records, and only the ones that appear in the actions table are showing.  Maybe this is supposed to be a Right outer join since I want all of the one table?
0
 
Rush_2112Author Commented:
That was it, I had to change it to a Left Outer Join.  But your code got me there!  Thanks so much!
0
 
Rush_2112Author Commented:
great job!
0
 
_agx_Commented:
No, a left join should give you exactly that.  Notice in my example UniqueID = 14 only exists in Master, not Actions. But 14 is included in the results.  (I just got a chance to test the example and can confirm it works as described).

Are you sure you're using the 1st example? ie

       SELECT  *
       FROM     Master a LEFT JOIN Actions b
                            ON  a.UniqueID = b.DealerID
                            AND b.EventID =  3
        WHERE b.DealerID IS NULL
0
 
_agx_Commented:
Whoops, sorry didn't see your replies before responding :) Glad it's solved.
0
 
Rush_2112Author Commented:
This is working, but it take a VERY long time to run the query, over 30 secs usually.  The 2 table involved aren't that big, is there something I could do to speed this up?

Thanks
0
 
_agx_Commented:
Sorry didn't this til now ..  (I usually stop monitoring once a thread is solved)

(Though  probably not the cause of the slowness, getting rid of "SELECT *" is always a good move. ) A query like this should not normally take long ..  

- How many rows are we talking about?
- Are there any other related columns between the 2 tables?
- Run the query in your db and look at the execution plan. It will tell you what is taking so long (table scan, cartesian product,etc...)
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.