resource mysql_query( string query [, resource connection] )

<php
$conn = @mysql_connect("localhost","root","root123");
if (!$conn){
 die("连接数据库失败：" . mysql_error());
}
mysql_select_db("test", $conn);
$result = mysql_query("SELECT * WHERE 1=1")
  or die("无效查询: " . mysql_error());
?> 
该例子查询语句在 SQL 语法上有错误，因此 mysql_query() 执行失败并返回 FALSE 。
例子2：
<php
$conn = @mysql_connect("localhost","root","root123");
if (!$conn){
  die("连接数据库失败：" . mysql_error());
}

mysql_select_db("test", $conn);
mysql_query("set names 'gbk'"); //为避免中文乱码做入库编码转换
$password = md5("123456"); //原始密码 12345 经过加密后得到加密后密码
$regdate = time();  //得到时间戳
$sql = "INSERT INTO user(username, password, email, regdate)VALUES('小王', '$password',
 '12345@163.com', $regdate)";

if(!mysql_query($sql,$conn)){
  echo "添加数据失败：".mysql_error();
} else {
  echo "添加数据成功！";
}
?> 

CREATE DATABASE db_name

<"localhost","root","root1234");
if (!$conn){
  die("连接数据库失败：" . mysql_error());
}
if (@mysql_query("CREATE DATABASE testdb",$conn)){
  echo "创建数据库成功！";
} else {
  echo "创建数据库失败：" . mysql_error();
}
?>

bool mysql_select_db( string db_name [, resource connection] )

CREATE TABLE table_name
(
  column1 data_type,
  column2 data_type,
  column3 data_type,
  .......
)

<"localhost","root","root1234");
if (!$conn){
  die("连接数据库失败：" . mysql_error());
}

//选择数据库
mysql_select_db("test", $conn);

//创建数据表 SQL
$sql = "CREATE TABLE user (
uid mediumint(8),
username varchar(20),
password char(32),
email varchar(40),
regdate int(10)
)";

if(!mysql_query($sql,$conn)){
  echo "创建数据表失败：". mysql_error();
} else {
  echo "创建数据表成功！";
}
?>