Combine select statements with php and sort by time - php

Question

So I have 5 separate select statements.
<?
$stmt=$db->prepare('SELECT * FROM table1 WHERE username = :username');
$stmt->bindParam(':user', $username);
$stmt->execute();
$row = $stmt->fetchAll();
$stmt=$db->prepare('SELECT * FROM table2 WHERE username = :username');
$stmt->bindParam(':user', $username);
$stmt->execute();
$row = $stmt->fetchAll();
$stmt=$db->prepare('SELECT * FROM table3 WHERE username = :username');
$stmt->bindParam(':user', $username);
$stmt->execute();
$row = $stmt->fetchAll();
$stmt=$db->prepare('SELECT * FROM table4 WHERE username = :username');
$stmt->bindParam(':user', $username);
$stmt->execute();
$row = $stmt->fetchAll();
$stmt=$db->prepare('SELECT * FROM table5 WHERE username = :username');
$stmt->bindParam(':user', $username);
$stmt->execute();
$row = $stmt->fetchAll();
?>
I need to combine all the results, organize all the results based on time with the newest time first, and then echo a message based on which table the result came from.
Note each table has a row time.
Example results:
<p>This result was posted 5 minutes ago and came from table 2</p>
<p>This result was posted 10 minutes ago and came from table 5</p>
<p>This result was posted 1 day 6 hours ago and came from table 1</p>
<p>This result was posted 2 weeks ago and came from table 3</p>
<p>This result was posted 3 weeks ago and came from table 1</p>
UPDATES:
Selecting * is an absolute requirement, which is why using mysql is not a viable solution. Mysql can't do full table joins, and instead mirrors the practice by doing cross joins of the tables. However if you understand the woe's of cross joins, you will understand when I say some of these tables will return thousands of results for a user, making cross joins not viable as cross joins will create countless duplicate rows for each entry, and having thousands of entries makes for millions and tens of millions of rows when doing a cross join. PHP seems to be the only solution.
I need a solution that wil use php to combine the selects and sort them based on time NOT a mysql solution.

Answer 1

You can define a new column in each table to hold the tablename. And then this kind of query can solve your problem:
SELECT username,timestamp,tableName from table1 union
select username,timestamp,tableName from table2 order by 2 desc

Answer 2

I think the problem should be solved where it belongs. This is obviously a db problem.
But as you have other concerns then you can try first fetching all rows from tables to an array. All tables should be selected with an order by descending timestamp field. Define a pointer for every table which shows the newest item in the related table. In your loop find the newest record amongst the rows which these pointers pointing to. and increase this pointer after printing out the info. Hope it helps. Here is an example:
$stmt=$db->prepare('SELECT * FROM table1 WHERE username = :username order by timestamp desc');
$stmt->bindParam(':username', $user);
$stmt->execute();
$row[0] = $stmt->fetchAll();
$stmt=$db->prepare('SELECT * FROM table2 WHERE username = :username order by timestamp desc');
$stmt->bindParam(':username', $user);
$stmt->execute();
$row[1] = $stmt->fetchAll();
// table lengts
$table_len[0]=sizeof($row[0]);
$table_len[1]=sizeof($row[1]);
//initialize every table pointers to 0
$table_pointer[0]=0;
$table_pointer[1]=0;
while ($table_pointer[0]<$table_len[0] ||
$table_pointer[1]<$table_len[1]){
// find the newest time
$time1=strtotime($row[0][$table_pointer[0]]['timestamp']);
$time2=strtotime($row[1][$table_pointer[1]]['timestamp']);
$tableWithNewestTime=findNewestTime($table_len,$table_pointer,$time1,$time2);
$timeDif=time()-strtotime($row[$tableWithNewestTime][$table_pointer[$tableWithNewestTime]]['timestamp']);
echo "This result was posted ".$timeDif." s ego and posted from table".($tableWithNewestTime+1)."<br>";
// increase the table pointer
$table_pointer[$tableWithNewestTime]=$table_pointer[$tableWithNewestTime]+1;
}
function findNewestTime(array $table_len, array $table_pointer, $time1,$time2){
if ($table_pointer[0]>=$table_len[0])
return 1;
if ($table_pointer[1]>=$table_len[1])
return 0;
if($time1<$time2)
return 1;
else
return 0;
}