GROUP BY statement returns different values in row table

[SimonIoa]

Hello i have a Mysql statement that supposes to return to results.

The statement is

SELECT c.user_one,c.user_two,c.c_id,r.reply
 FROM conversation_reply r
JOIN conversation c ON r.c_id_fk = c.c_id 
 WHERE c.user_one = '3'
 OR c.user_two = '3'
 GROUP BY r.reply

I have only two records in the table so the result should be:

   user_one   user_two   c_id     reply

     2          1         43     Hello One
     1          2         43     Hello Two 

Instead its like

    user_one   user_two   c_id     reply

     2          1         43     Hello One
     2          1         43     Hello Two 

If i loose the GROUP BY it returns 4 records but i only have two, like this

    user_one   user_two   c_id     reply

     1          2         43     Hello One
     2          1         43     Hello Two 
     1          2         43     Hello One
     2          1         43     Hello Two 

Any idea why?

[pritaeas]

Because you are only grouping on r.reply. Since there are only two differect replies,

With what you've shown the group by could be GROUP BY c.user_one, c.user_two, c.c_id, r.reply and you'll get your expected result. I cannot predict the impact on the rest of your data though.

Another way to eliminate dupes is to SELECT DISTINCT c.user_one,c.user_two,c.c_id,r.reply and remove the GROUP BY altogether.