PER 마지막 행을 가져옵니다. 내가 얻을하려는 각 행에 대해 , 대화 첫 번째 행의 "날짜 시간" "메시지"그것을하는 방법은 아래의 작업에 대한 쿼리를 공식화 할 수 그룹
CREATE TABLE messages ( ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY, FromID INT NOT NULL, ToID INT NOT NULL, ConversationID INT NOT NULL, Subject varchar(255), Message varchar(255), DateTime DATETIME ) ENGINE=InnoDB; CREATE TABLE conversations ( ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY ) ENGINE=InnoDB; INSERT INTO conversations (ID) VALUES (1), (2), (3); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (1,2, 1, "Hi", "This is a test message", "2010-08-08 16:23:48"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (1,2, 1, "", "Hey again you have not answered", "2010-08-08 16:23:52"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (2,1, 1, "", "Hi this is my answer", "2010-08-08 16:23:59"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (2,1, 2, "2.Hi", "2.This is a test message", "2010-08-08 16:25:48"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (1,2, 2, "", "2.Hi back", "2010-08-08 16:25:52"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (2,1, 2, "", "2.Hi this is my answer", "2010-08-08 16:25:59"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (2,1, 3, "3.Hi", "3.This is a test message", "2010-08-08 16:27:48"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (1,2, 3, "", "2.Hi back", "2010-08-08 16:27:52"); INSERT INTO messages (FromID, ToID, ConversationID, Subject, Message, DateTime) VALUES (1,2, 3, "", "2.Hello are you there?", "2010-08-08 16:27:59");
있습니까? 즉, 대화 내 모든 메시지에 대해 사용자 ID가 'FromID'또는 'ToID'가 될 것인가? –
네 대화는 두 사람 사이에서만 가능합니다 – user391986