MySQL - Conversation History overview - Selecting multiple latest items from table - php

Question

I have the joy of recreating the phone, by building a customized messaging system in PHP that uses an API to send and receive messages.
I'm trying to emulate the functionality found in Facebook messaging on their desktop site.
[Col 1] [Col 2]
A list of the Conversation View.
latest messages
received in order
of Newest to oldest
I am having issues with the Query for the first column.
I currently have a table in MySQL with the following structure:
CREATE TABLE IF NOT EXISTS `History` (
`ID` int(10) NOT NULL AUTO_INCREMENT COMMENT 'MessageID',
`Sender` varchar(10) NOT NULL,
`Recipient` varchar(10) NOT NULL,
`ExtReference` int(20) DEFAULT NULL,
`Date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`Status` varchar(100) NOT NULL,
`userid` int(3) NOT NULL,
`Message` longtext NOT NULL,
PRIMARY KEY (`ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=609 ;
With a sample Date set like:
INSERT INTO `History` (`ID`, `Sender`, `Recipient`, `ExtReference`, `Date`, `Status`, `userid`, `Message`) VALUES
(1, '0412345678', '0468888888', 33845909, '2013-03-17 04:17:34', '1', 11, 'Just testing....'),
(2, '0412345678', '0400222333', 33845910, '2013-03-17 04:17:35', '1', 11, 'Amazing'),
(3, '0412345678', '0411111111', 33847419, '2013-03-17 04:46:04', '1', 8, 'Nothing here to see'),
(4, '0412345678', '0400222333', 33850155, '2013-03-17 06:31:57', '1', 12, 'Hello there Mr IT Guru :-)'),
(5, '0400222333', '0412345678', 33850179, '2013-03-17 06:33:21', '1', 12, '[Write message here]'),
(6, '0412345678', '0411111111', 33955423, '2013-03-23 01:26:22', '1', 8, 'Hello Charles'),
(7, '0412345678', '0411111111', 33959071, '2013-03-23 03:08:26', '1', 13, 'Sample Message'),
(8, '0400222333', '0412345678', 33964111, '2013-03-23 05:27:51', '1', 13, 'How do I use this system?'),
(9, '0400222333', '0412345678', 34107503, '2013-03-30 03:13:38', '1', 12, 'Is this thing on?'),
(10, '0412345678', '0401411210', 34230869, '2013-03-05 00:18:09', '1', 16, 'Hello')
(In this example my number is: 0412345678).
SQL Fiddle here: http://sqlfiddle.com/#!2/29197/1/0
I have worked out how to get a list of all the unique numbers used across both the Sender and Recipient columns:
SELECT DISTINCT `Sender` AS phoneID FROM `History`
UNION
SELECT DISTINCT `Recipient` AS phoneID FROM `History`
But I can't work how to attach the latest Date and message to this data.
If I focus on either just messages sent to me or sent by me I can get somewhere with these two:
SELECT `ID`, `Sender`, `Recipient`, MAX(`Date`), `Message` FROM History
GROUP BY Sender
ORDER BY `History`.`Date` DESC
or
SELECT `ID`, `Sender`, `Recipient`, MAX(`Date`), `Message`, `Status` FROM History
GROUP BY Recipient
ORDER BY `History`.`Date` DESC
Any thoughts?
I can recreate the History table layout if needed.
I'll also need to try and join the phone number with a persons name in a Contacts table later on down the track.
Thanks
Charlie

Answer 1

Possibly not the best way but you could combine the two queries you have. Something like:
SELECT `ID`, `Sender`, `Recipient`,`Date`,`Message`,`Status` FROM
(
SELECT `ID`, `Sender`, `Recipient`, `Date`, `Message`,`Status` FROM History
WHERE Sender = "0412345678"
GROUP BY Sender
UNION
SELECT `ID`, `Sender`, `Recipient`, MAX(`Date`), `Message`, `Status` FROM History
WHERE Recipient = "0412345678"
GROUP BY Recipient
) res
GROUP BY res.ID
ORDER BY res.Date DESC
Note that this is for a specific number. You could remove the WHERE clauses if this wasn't needed.