Ich brauche wenig Hilfe beim Lesen meiner "chats" SQL-Tabelle.SQL SELECT - Chats
Säule:
Chat_ID - decimal(18, 0) primary key, inflexible-yes
Sent_ID - decimal(18, 0)
Receive_ID - decimal(18, 0)
Time - datetime
Message - nvarchar(MAX)
Sent_ID| Receive_ID | Time | Message
-------+----------+------------------+-----------------
1 | 2 | 11/21/2015 10:00 | Hey! test
-------+----------+------------------+-----------------
2 | 1 | 11/21/2015 10:50 | Hi! respond
-------+----------+------------------+-----------------
1 | 2 | 11/21/2015 10:51 | respond 3
-------+----------+------------------+-----------------
2 | 1 | 11/21/2015 11:05 | respond final
-------+----------+------------------+-----------------
1 | 3 | 11/21/2015 11:51 | Message 1
-------+----------+------------------+-----------------
3 | 1 | 11/21/2015 12:05 | Message 2
-------+----------+------------------+-----------------
1 | 3 | 11/21/2015 12:16 | Message Final
-------+----------+------------------+-----------------
4 | 1 | 11/21/2015 12:25 | New message 1
-------+----------+------------------+-----------------
Wie kommt man ... (letzte Nachricht mit jedem Benutzer?)
Sent_ID| Receive_ID | Time | Message
-------+----------+------------------+-----------------
2 | 1 | 11/21/2015 11:05 | respond final
-------+----------+------------------+-----------------
1 | 3 | 11/21/2015 12:16 | Message Final
-------+----------+------------------+-----------------
4 | 1 | 11/21/2015 12:25 | New message 1
-------+----------+------------------+-----------------
Man merkt, dass ich brauche so etwas wie: MAX (Time), WO (Sent_ID = @ Sent_ID oder Receive_ID = @ Receive_ID) in diesem Fall ........... Sent_ID = 1 ..... Receive_ID = zu vereinfachen: WHERE (Sent_ID = 1 oder Receive_ID = 1)
Danke ....
Welche DBMS verwenden Sie? –