Why does PHP DATE_ADD() function returns a syntax error

Question

Im trying to populate a table using some other specific tables(there's a set of tables known as table_1,table_2,table_3 etc) in the same database by giving a date interval(to obtain rows which are recorded within a month). below is the code im using

<?php
include("functions.php");
connect();
$table_count = mysql_query("SELECT COUNT(*) AS cnt FROM information_schema.tables WHERE table_schema = 'mydb' AND table_name LIKE 'mytable_%'");



$row = mysql_fetch_assoc($table_count);
$loop_var = ($row["cnt"]);


for ($x=1; $x<=$loop_var; $x++) {


mysql_query("INSERT INTO stats (`useragent_browser`, `useragent_OS`, `timestamp`)
SELECT `useragent_browser`, `useragent_OS`, `timestamp` FROM table_'.$x.'
WHERE `timestamp` > DATE_ADD(NOW(), INTERVAL -1 MONTH)") or die(mysql_error());
}
?>

but at the moment this returns as errror saying

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''.1.' WHERE timestamp > DATE_ADD(NOW(), INTERVAL -1 MONTH)' at line 2

can anybody help on me soughting this out

Answer 1

Try this:

mysql_query("INSERT INTO stats (`useragent_browser`, `useragent_OS`, `timestamp`)
SELECT `useragent_browser`, `useragent_OS`, `timestamp` FROM table_$x
WHERE `timestamp` > DATE_ADD(NOW(), INTERVAL -1 MONTH)") or die(mysql_error());
}

or

mysql_query("INSERT INTO stats (`useragent_browser`, `useragent_OS`, `timestamp`)
SELECT `useragent_browser`, `useragent_OS`, `timestamp` FROM table_".$x."
WHERE `timestamp` > DATE_ADD(NOW(), INTERVAL -1 MONTH)") or die(mysql_error());
}