法1：
if(mysql_num_rows(mysql_query("SHOW TABLES LIKE '".$table."'"))==1) echo "Table exists";
else echo "Table does not exist";
法2：
function TableExists($tablename, $db) {
// Get a list of tables contained within the database.
$result = mysql_list_tables($db);
$rcount = mysql_num_rows($result);
// Check each in list for a match.
for ($i=0;$i<$rcount;$i++) {
if (mysql_tablename($result, $i)==$tablename) return true;
}
return false;
}