problem with mysql_query

[cubx]

Here is the snipped of code I'm using:

if (!isset($_POST['Submit']))
    form();
else
if (!blank_field())
      echo "fields left blank";
    else
    if (checklength($_POST[password], 5, 15))
      echo "password length incorrect";

if (connect_to_db()) {
    $query = "select username from accounts where username='[username]'";

    $result = $mysql_query($query, $link);
    if ($result) // true = user already exists
        echo "User already exists";
    else
        echo "You are a new user";
}

The blank fields and wrong password length are working fine. I am using mysql 5.0.27, php 5.2.0, and apache 2.2.3, if that matters.

I created the database and added in 2 users using the command line. I have a form that asks for a username and password, then this part of the code is supposed to check the form username with the mysql username for duplicates.

I don't get any errors, even though I am typing in the same name, which should result in "User already exists". All it does is lets me enter the information, and keeps going.

Any pointers? Do I need to post the entire php file?

[Flukey]

[code=php:0] $result = $mysql_query($query, $link) or die(mysql_error()); [/code]

See if there is a mysql error. :)

[cubx]

There are no errors showing. I even added the die statement like you said and tried again. I put in a username which does exist, so I should have receive a duplicate username warning.

Nothing. It just proceeds as normal. Obviously something is wrong.

[HuggieBear]

Try changing this:
[code=php:0]$query = "select username from accounts where username='[username]'";[/code]

To this:
[code=php:0]$query = "select username from accounts where username='{$_POST['username']}'";[/code]

Regards
Huggie

[cubx]

Ok I did that. Now my code looks like this:

if (connect_to_db()) {
    $query = "select username from accounts where username='{$_POST['username']}'";
    $result = $mysql_query($query, $link) or die(mysql_error());
      echo "$result";
//    if ($result) // true = user already exists
//        echo "User already exists";
//    else
//        echo "You are a new user";
}

I'll remove the comments once I know it's working. Anyway, there are no errors, the page goes blank.

I get no results at all. I keep looking over google for examples like this, but can't find anything. What I'm trying to do is have the form pass a username to php, which calls mysql, does a search for the username, and says it is exists. For the life of me, I cannot find any tutorials online where someone else has done this. I can't imagine I'm the first.

[HuggieBear]

OK, here's a complete code, assuming that the fields in your form are called username and password and you're using the post method.

[code]<?php
// Have the username and password been filled out
if (!empty($_POST['username']) && !empty($_POST['password'])){
  // Query the database
  $sql = "SELECT username FROM users WHERE username = '{$_POST['username']}'";

  // Check if we got a result returned
  $result = mysql_query($sql);
  if (!$result){
      echo "Couldn't execute: $sql<br><br>\n" . mysql_error();
  }
  else {
      // Does the user exist, how many rows were retrurned
      if (mysql_num_rows($result) > 0){
        echo "Username already in use\n";
      }
      else {
        echo "Username doesn't exist\n";
      }
  }
}
else {
  // Your code to echo the form goes here
}
?>[/code]

Regards
Huggie

[pradeep_achean]

how the future will be in php
how the projects will  be coming

[cubx]

Huggie... I replaced my code with yours. Yours is much cleaner. However, I am still not getting any database feedback. I type in my username on the form, which I manually added to mysql on my linux server, but after I click submit, I get nothing. No errors, not even the echo statement saying if the username exists.

Everything is running fine on my linux machine. I just checked it. I can't figure this out.

Here is the script:

<?php

// Have the username and password been filled out

function form(){
        echo "<table width=\"100%\" height=\"5%\" bgcolor=\"cyan\">";
        echo "<tr>";
        echo "<td bgcolor=\"white\" width=\"20%\"><font color=\"green\">&nbsp;&nbsp;&nbsp;<font size=+1><b>Step 1</b></font></td>";
        echo "<td>&nbsp;&nbsp;&nbsp;<font size=+1 color=\"white\"><b>Step 2</b></font></td>";
        echo "<td>&nbsp;&nbsp;&nbsp;<font size=+1 color=\"white\"><b>Step 3</b></font></td>";
        echo "<td>&nbsp;&nbsp;&nbsp;<font size=+1 color=\"white\"><b>Step 4</b></font></td>";
        echo "<td>&nbsp;&nbsp;&nbsp;<font size=+1 color=\"white\"><b>Step 5</b></font></td>";
        echo "</tr>";
        echo "<tr bgcolor=\"white\">";
        echo "<td bgcolor=\"red\" width=\"20%\">&nbsp;&nbsp;&nbsp;<b><i><font size=+1>LOG IN</i></b></td>";
        echo "<td></td>";
        echo "<td></td>";
        echo "<td></td>";
        echo "<td></td>";
        echo "</tr>";
        echo "</table>";

        echo "<br><br><br><br><br><br><br><br><br><center>";
        echo "<table border=\"0\" bgcolor=\"#66ccff\" cellpadding=\"10\">";
        echo "<form action='" .$_SERVER['PHP_SELF'] ."' method='post'>";
        echo "<tr><td>What username do you want?</td><td><input type='text' name='username'></td>";
        echo "<tr><td>Pick a password (5-15 characters):</td><td><input type='password' name='password'></td>";
        echo "<tr><td colspan=2 align=center><br><input type='image' name='Submit' value='Submit' src='submit.gif'>";
        echo "</form>";
        echo "</table></center>";
}
       
function connect_to_db() {
    $link = mysql_connect('localhost', 'user', 'password');
    if (!$link) {
        die('Could not connect: ' . mysql_error());
        }

    $db_selected = mysql_select_db('mydb', $link) or die(mysql_error());
    if (!$db_selected) {
        echo "Cannot use database<br>";
        echo "mysql_error()";
        }
}

function blank_field(){
    while(list($name,$val)=each($_POST)){
        if (!$val)
            return FALSE; // if fields are blank
    }
    return TRUE;
}

if (!isset($_POST['Submit']))
    form();
else

if (connect_to_db()) {

if (!empty($_POST['username']) && !empty($_POST['password'])){
  // Query the database
  $sql = "SELECT username FROM users WHERE username = '{$_POST['username']}'";

  // Check if we got a result returned
  $result = mysql_query($sql);
  if (!$result){
      echo "Couldn't execute: $sql<br><br>\n" . mysql_error();
  }
  else {
      // Does the user exist, how many rows were retrurned
      if (mysql_num_rows($result) > 0){
        echo "Username already in use\n";
      }
      else {
        echo "Username doesn't exist\n";
      }
      echo "here is the form";
      } // end else
} // end if
} // end while
?>

What could I possibly be missing? I at least expected it to say if the username exists, but it doesn't.

[HuggieBear]

Add the following to the top of your code...

[code=php:0]error_reporting(E_ALL);[/code]

Regards
Huggie

[cubx]

Ok I got it working. Even the error reporting thing didn't help. What it turned out to be is in the connect_to_db function, after the part where it dies if it fails, I needed an "else" there, and at the end of the function, it wasn't returning a value, which apparently the main loop was expecting. I added the else, return TRUE, and now it works.

Thank you!