用于查询所需数据库帮助的脚本

i have the following code in php:

$host="localhost"; // Host name
$username="***"; // username
$password="***"; // password
$db_name="***"; // Database name
//$rc_profile_table="rc_profile_table"; // Table name
//$rc_profile_relation_table="rc_profile_relation_table"; // Table name


mysql_connect("$host", "$username", "$password");
mysql_select_db("$db_name");

$sql="SELECT created_at FROM rc_profile_table where created_at > 2011-04-19 08:00:00";
$result=mysql_query($sql);
$count=mysql_num_rows($result);

$sql="SELECT created_at FROM rc_profile_relation_table where created_at > 2011-04-19 08:00:00";
$result2=mysql_query($sql);
$count2=mysql_num_rows($result);

 mysql_close();

You have no proper error handling. The mysql functionality provided with php have a build in function that outputs the error on the screen. This would be a lot better:

<?php
$host="localhost"; // Host name 
$username="***"; // username 
$password="***"; // password 
$db_name="***"; //db name

$connection = mysql_connect($host, $username, $password) or die("Could not connect to the database: " . mysql_error()); 
mysql_select_db($db_name, $connection) or die("Could not select database: " . mysql_error());

$sql = "SELECT `created_at` FROM `rc_profile_table` WHERE `created_at` > '2011-04-19 08:00:00'"; 
$result = mysql_query($sql) or die("Could not execute query: " . $sql . "ERROR: " . mysql_error()); 
$count = mysql_num_rows($result);

mysql_close($connection) or die(mysql_error());

?>

What do you actually want to do? You have to describe the problem else no one can help you...

In addition to the error handling already mentioned, for your second resultset, you might want to ensure that $count2 is the number of rows returned in $result2 rather than in the first resultset ($result)

$sql="SELECT created_at FROM rc_profile_relation_table where created_at > 2011-04-19 08:00:00"; 
$result2=mysql_query($sql); 
$count2=mysql_num_rows($result2);