I am using MYSQL database.
I have a table with four columns id, sender, reciever and recieverread;
reciever and sender columns can contain duplicate values is there a way to select only the last row with the duplicate value?
I tried
SELECT DISTINCT sender FROM msg WHERE sender = sender
You can try something like this:
SELECT sender FROM msg GROUP BY sender HAVING COUNT(sender) > 1;
This will prevent to data duplication. You may try this,
SELECT DISTINCT sender FROM msg WHERE sender = sender group by sender
How about:
SELECT MAX(id) AS id_last, sender, receiver, recieverread FROM msg GROUP BY sender, receiver, recieverread
try this
select maxid ,sender from msg where id in (
select max(id) as maxid from msg GROUP BY sender)
A standard way to approach this in MySQL is with a not exists clause:
select m.*
from msg m
where not exists (select 1 from msg m2 where m2.sender = m.sender and m2.id > m.id);
That is, select the row for a given sender that has no larger ids in the table.
SHOW CREATE TABLEfor your table, and some sample datasender? How do you know which row it is coming from?