Question

php与mysql的查询语句的问题？？

假设我有表user里有
id username password
帮我写一下。。实现一下内容:
①查询出id为3的用户的username然后显示出来。
②查询username字段里是否有个叫admin的用户。然后用if...else判断有则输出:"抱歉已近有该用户"没有就显示"成功"

Answer 1

(1) select username from user where id='3';
(2)
$username=your_name;
$userpass=your_pass;
$dbhost=localhost;
$dbdatabase=your_database;
//生成一个连接
$db_connect=mysql_connect($dbhost,$username,$userpass) or die("Unable to connect to the MySQL!");
//选择一个需要操作的数据库
mysql_select_db($dbdatabase,$db_connect);
//执行MySQL语句
$result=mysql_query("select * from user where username='admin'");
if(result !=false)
echo "<script>alert('成功')</script>";

else
echo "<script>alert('抱歉已近有该用户')</script>";