Question

Let’s say I have a screenshots table and a replies table. So: every screenshot can have multiple replies (one-to-many). Now, I want to create a combined timeline of the two, but in reality, they’re pretty unrelated (in structure).

How can I select data from both tables, ordering by their publish time, descending; when for example, I can have a post, a few comments, then another post; because that would be how the timeline happened?

Normally selecting from both combines the tables; but I don’t want that to happen. On that subject, I also need the tables to be distinguishable. Here’s the structure for the tables…

--
-- Table structure for table `screenshots`
--

CREATE TABLE IF NOT EXISTS `screenshots` (
  `id` int(11) NOT NULL auto_increment,
  `user` int(11) NOT NULL,
  `description` text NOT NULL,
  `time` timestamp NOT NULL default CURRENT_TIMESTAMP,
  `ext` varchar(4) NOT NULL default 'png',
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=14 ;

-- --------------------------------------------------------

--
-- Table structure for table `screenshot_replies`
--

CREATE TABLE IF NOT EXISTS `screenshot_replies` (
  `id` int(11) NOT NULL auto_increment,
  `user` int(11) NOT NULL,
  `parent` int(11) NOT NULL,
  `time` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
  `text` text NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;

Note: I realize this may be a duplicate of this question but I didn’t find the solution there working for me.

Thanks in advance! 🙂

Answer 1

You should use UNION in this case:

(SELECT id, time, 'screenshots' as tableName FROM screenshots)
UNION
(SELECT id, time, 'replies' as tableName FROM screenshot_replies)
ORDER BY time ASC

You can get the tablename of a field by using the mysql_tablename function in php
You can indicate the tablename as a column in the result set