现在数据库中已经有了数据。如果我们要从中获取数据,我们需要SELECT命令。抓取数据的选择有多个。
第一, 从数据库中抓取整个数据表
SELECT * FROM `tablename`
这里的PHP脚本用来解释这一示例。该脚本将整个MySQL数据包抓取出来并将其显示在你的浏览器中。
//Step 1 Connect to database
$username = "Your MySQL username here";
$password = "Your MySQL password";
$hostname = "Hostname";
$table = "MySQL Table name where the data will be ed";
$database = "The name of the MySQL database which holds the table";
$dbhle = mysql_connect($hostname, $username, $password)
or die("Unable to connect to MySQL");
$ed = mysql__db($database,$dbhle)
or die("Could not $database");
//Step 2. Insert other PHP scripts here (such as grabbing data from HTML forms, etc)
//Step 3. Sanitize variables before ing to database. This will prevent MySQL injection.
$categories_id = mysql_real_escape_string(stripslashes($categories_id));
$language_id = mysql_real_escape_string(stripslashes($language_id));
$categories_name = mysql_real_escape_string(stripslashes($categories_name));
$result = mysql_query("SELECT * FROM `categories_description`")
or die(mysql_error());
echo
Categories ID | ;Language ID | ;Categories Name | ;
.$row[categories_id]. | ;.$row[language_id]. | ;.$row[categories_name]. | ;
?>
这样在HTML浏览器中会显示出该表格,像这样:
第二种是从MySQL表格的指定域名中提取指定数据。当你需要从满足特定条件的指定域名中提取指定数据的时候,如:我们需要提取客户邮件地址的时候如果他们也能准确提供用户名和密码。那么在表格中就存在三个域:用户名,密码,电子邮件地址。那么要在MySQL表格中提取客户电子邮件地址,PHP查询可以是:
//Connect to database...
//Sanitize the variables..
//MySQL query
$result = mysql_query("SELECT `emailaddress` FROM `customertable` WHERE `username`=$username AND `password`=$password")
or die(mysql_error());
$row = mysql_fetch_array($result)
or die("Invalid query: " . mysql_error());
$emailaddress = $row[emailaddress];
echo "Your email address is: $emailaddress";
?>
在PHP MySQL查询中,WHERE陈述指定了邮件地址匹配特定用户名和密码的条件。
你可以用一些AND语句来查询MySQL。
UPDATE MySQL查询命令
PHP中最重要的MySQL查询之一还有UPDATE。如命令所示,它可以让你更新MySQL表格中的记录,而不需要再次插入一行。
例如,假设你拥有下表:
假设Peter Patter要将密码从“logan”改成“weaponx”,那么使用UPDATE的MySQL查询应该是:
//Step 1 Connect to database
$username = "yourusername";
$password = "yoursqlpassword";
$hostname = "localhost";
$table = "usertable";
$database = "userdatabase";
$dbhle = mysql_connect($hostname, $username, $password)
or die("Unable to connect to MySQL");
$ed = mysql__db($database,$dbhle)
or die("Could not $database");
//Initial variables
$username = wolverine;
$fullname = Peter Patter;
//Set new password for Peter Patter
$newpassword = weaponx;
//sanitize
$newpassword = mysql_real_escape_string(stripslashes($newpassword));
$username = mysql_real_escape_string(stripslashes($username));
$fullname = mysql_real_escape_string(stripslashes($fullname));
//Update records in MySQL database
mysql_query("UPDATE usertable SET password = $newpassword WHERE username = $username AND fullname = $fullname")
or die(mysql_error());
echo The database has been d. Thank you;
?>
上面的更新脚本会将Peter Patter的密码从 “logan”改成“weaponx”。上面的脚本只是一个示范,你可以用上面的脚本和HTML表单结合,这样可以创建更多的互动性更新数据。