Question

I have a table with 4 columns:

ID, USER_ID, SOURCE, CREATED_DATE

In that table is the following data:

ID  USER_ID SOURCE          CREATED_DATE
1   25      PURCHASE        2012-01-01 12:30:00
2   26      PLEDGE          2012-01-01 12:40:00
3   25      PLEDGE          2012-01-01 12:50:00
4   25      PURCHASE        2012-01-14 12:00:00

Now as you can see, I have 4 rows of data, and two unique users. User (25) made 3 transactions (two purchases and one pledge), user (26) made one transaction – (one pledge)

Here is what I am trying to achieve:

I need to select ALL transactions from this table, but I want to select a UNIQUE user for each REQUEST TYPE (source), and that row needs to be the EARLIEST TRANSACTION.

My expected result data would be:

ID  USER_ID SOURCE          CREATED_DATE
1   25      PURCHASE        2012-01-01 12:30:00
2   26      PLEDGE          2012-01-01 12:40:00
3   25      PLEDGE          2012-01-01 12:00:00

User (25) made TWO PURCHASES (one on 2012-01-01 and one on 2012-01-14) – the first is the one that gets returned.

This is the SQL I have come up with so far:

    SELECT 
        Supporter.user_id,
        MIN(Supporter.created) as created,
        Supporter.*,
        Supporter.source
    FROM
        supporters AS Supporter

    GROUP BY Supporter.source
    ORDER BY Supporter.created ASC

Now, this gets me really close, except it only selects ONE of the user id’s (the one with two items – a pledge and a purchase). If I could figure out how to select the data on both users, that would be what I need to do! Can anyone see what I am possibly doing wrong here, or missing?

Answer 1

You need to group by source and by user id

Something like this

SELECT 
    Supporter.user_id,
    MIN(Supporter.created) as created,
    Supporter.*,
    Supporter.source
FROM
    supporters AS Supporter

GROUP BY Supporter.user_id, Supporter.source
ORDER BY Supporter.created ASC