Data cannot be written to the database solution ideas

Data cannot be written to the database
Session_Start ();
[Email Protected]_connect ("localhost", "root", "ch12345") or Die ("Database link error");
mysql_select_db ("Literature", $coon);
mysql_query ("Set names ' UTF-8 '");
@ $username =$_post[' username ');
@ $password =$_post[' password ');
@ $email =$_post[' email '];
@ $sex =$_post[' sex '];
@ $constallation =$_post[' constallation ');
$time =time ();
$STR = "SELECT * from user where username={$username}";
$result 1= $coon->query ($STR); This line is wrong, how should it be changed?
$row = $result 1->fetch_row ();
if ($row)
{
$temp = "Someone has registered this name, please re-select the name!";
Echo $temp;
echo "Back";
}
else {
$sql = "INSERT into user (Username,sex,time,constallation,password,email)".
"VALUES (' $username ', ' $sex ', now (), ' $constallation ', ' $password ', ' $email ')";
$sql = "INSERT into user VALUES ($username, $sex, $time, $constallation, $password, $email)";
$result = $coon->query ($sql);
if ($result ==true)
{
$_session[' mail ']= "Registration is successful, please login";
echo "";
}
else {echo "registration failed". Mysql_error ();}
}
?>

------Solution--------------------
discuss
$result 1= $coon->query ($STR); This line is wrong, how should it be changed?
$row = $result 1->fetch_row ();

------Solution--------------------
[Email Protected]_connect ("localhost", "root", "ch12345") or Die ("Database link error");
$coon->query ($STR);
I haven't seen it like this before! Take a closer look at the manual first http://www.php.net/manual/zh/book.mysql.php
------Solution--------------------
discuss

[Email Protected]_connect ("localhost", "root", "ch12345") or Die ("Database link error");
$coon->query ($STR);
I haven't seen it like this before! Take a closer look at the manual first http://www.php.net/manual/zh/book.mysql.php

