用于查询数据库帮助的脚本

Question

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();

Answer 1

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

Answer 2

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());

?>

Answer 3

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);