PHP mysql search multiple tables using a keyword

Question

I have three tables in my database which are:

messages
topics
comments

Each of these tables has two fields called 'content' and 'title'. I want to be able to use 'Like' in my sql statement to look at 'messages.content', 'messages.title', 'topics.content', 'topics.title', 'comments.content' and 'comments.title' using a keyword.

So far, my query is able to find results from only one table:

mysql_query("SELECT * FROM messages 
WHERE content LIKE '%" . $keyword . "%' 
OR title LIKE '%" . $keyword ."%'");

I am also wondering, once I get the results from multiple tables, how can I tell what result is from what table?

Any help would be greatly appreciated!

Answer 1

$query = "(SELECT content, title, 'msg' as type FROM messages WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%') 
           UNION
           (SELECT content, title, 'topic' as type FROM topics WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%') 
           UNION
           (SELECT content, title, 'comment' as type FROM comments WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%')";

mysql_query($query);

So, you are getting result from all of the three tables, and you can identify which row came from which table by looking at its type value.