How do I retrieve a specific value from MySQL with PHP? - php

Okay I'm so fed up. I've spent the better part of my free time for the past week trying to figure this out. I know that the query has changed in SQL but I cant figure it out. All of the other posts I can find seem to be outdated. If anyone could help me out I would really appreciate it.
All I am trying to do is retrieve the id of a row by using a unique "passphrase" that I manually entered into a database and then set that as session data so that I can use that data on other pages. I feel like it shouldn't be this hard.
For demostration purposes here is my code using the older mysql_query.
<?php
$dbhost = 'localhost';
$dbuser = 'root';
$dbpass = 'test321';
$db = 'local_test';
$conn = mysql_connect($dbhost,$dbuser,$dbpass);
mysql_select_db($db); ?>
<?php
include 'includes/connection.php';
$pass = $_POST['inputPass'];
if(!$_POST['submit']) {
echo "please fill out the form";
header ('location: user_authenticate.php');
}
$query = "SELECT id FROM users WHERE pass= '$pass'";
$id = mysql_query($query);
$_SESSION["userId"] = "$id";
print $pass;
print $id;
print $_SESSION["userId"];?>
I've tried a lot of things so I've gotten a lot of different errors. I am hoping someone could point me in the right direction here. What is the best way to do this?

First off, don't use the mysql API; it's deprecated and won't work in PHP 7.
Now that that's out of the way, mysql_query() returns a result set resource (which is like an object) which can contain multiple rows which can contain multiple columns. To access the contents of this resource, you have to fetch a row into an array and then index into that array for the column you want. You need to do something like this:
$query = "SELECT id FROM users WHERE pass= '$pass'";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
$id = $row['id'];
and then you can use the value of $id.
The same holds for mysqli::query(), which returns a mysqli_result object.

Related

mysql problem using php when update table

This system is based on invitation codes, if u have a code that is present in the database you can submit the input therefore change a value in a row. There are 2 inputs, 1) Invitation Code (key), if exist in the database the user can submit the value 2)Name (user). I done the following code but it doesn't work, any suggestions?
<?php
//get value pass from form in login.php
$username = $POST['user'];
$password = $POST['key'];
//connect to the server and select database
mysql_connect("localhost", "...","...");
mysql_select_db("...");
// Query the database for user
$result = mysql_query("UPDATE invitation_keys SET name ='$username' WHERE key = '$password'";)
or die("Failed to query database".mysql_error());
$row = mysql_fetch_array($result);
if ($row['key'] == $password) {
echo "Login success!!!".$row['key'];
} else {
echo "Failed to login";
}
?>
When you are coding in PHP, var_dump($var) is your best friend.
So the first thing to do here, is to print the query.
You will see, that your $username and $password vars are NULL, because you missed the syntax of $_POST[].
After, you can put in var_dump what you want, and that's why its interesting, because you will debug faster with this.

Unique page for each row in database with PHP

I have been trying to create a unique page for each row in my database. My plan is to create a dictionary.php?word=title url, where I can display the description and title of that specific ID. My datbase is contains id, term_title and term_description.
I'm fresh outta the owen when it comes to PHP, but I've managed to atleast do this:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "dbname";
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Cannot connect to database." . mysqli_connect_error());
}
if (isset($_GET['id']))
{
$id = (int) $_GET['id'];
$sql = 'SELECT * FROM dbname WHERE id = $id LIMIT 1 ';
}
$sql = "SELECT * FROM terms";
$result = $conn->query($sql);
mysqli_close($conn);
?>
I'm really stuck and I dont know what the next step is, I've added the <a href='dictionary.php?=".$row["id"]."'> to each word I want to be linked, and this is properly displayed in the main index.php file (where all my words are listed with <li>. This is my code for this:
<?php
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "<a href='dictionary.php?=".$row["id"]."'><li class='term'><h4 class='term-title'>" . $row["term_title"]. "</h4></li></a>";
} else {
echo "No words in database.";
}
?>
How do I create this unique page, only displaying title and description for that id? How do I add ?word= to the url?
Thanks for taking your time to help me.
Update from years later: Please, please use parameters when composing your SQL queries. See Tim Morton's comment.
You're on the right track, and ajhanna88's comment is right, too: you want to be sure to include the right key ("word" in this case) in the URL. Otherwise, you're sending a value without telling the page what that value's for.
I do see a couple other issues:
When you click on one of the links you created, you're sending along $_GET["word"] to dictionary.php. In your dictionary.php code, however, you're searching for your word by "id" instead of by "word". I'm guessing you expect users to search your dictionary for something like "celestial" and not "1598", so try this instead:
if (isset($_GET['word'])) {
$word = $_GET['word'];
$sql = 'SELECT * FROM dbname WHERE word = $word LIMIT 1 ';
}
BUT! Also be aware of a security problem: you were letting the user put whatever they want into your query. Take a look at the classic illustration of SQL injection. To fix that, change the second line above to this:
`$word = $conn->real_escape_string($_GET['word']);`
Another problem? You're looking for the word exactly. Instead, you'll probably want to make it case insensitive, so "Semaphore" still brings up "semaphore". There are plenty of ways to do that. The simplest way in my experience is just changing everything to lowercase before you compare them. So that $word assignment should now look like this:
`$word = $conn->real_escape_string(strtolower($_GET["word"]));`
And your query should look something like this:
`$sql = "SELECT * FROM dbname WHERE word = LOWER('$word') LIMIT 1 ";`
Next! Further down, you overwrite your $sql variable with SELECT * FROM terms, which totally undoes your work. It looks like you're trying to show all the words if the user doesn't provide a word to look up. If that's what you're trying to do, put that line in an else statement.
Your $result looks fine. Now you just have to use it. The first step there is to do just like you did when you tested the connection query (if(!$conn)...) and check to see that it came back with results.
Once you have those results (or that one result, since you have LIMIT 1 in your query), you'll want to display them. This process is exactly what you did when printing the links. It's just that this time, you'll expect to have only one result.
Here's a real basic page I came up with from your code:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "dbname";
$conn=new mysqli($servername,$username,$password,$dbname);
if($conn->connect_errno){
die("Can't connect: ".$conn->connect_error);
}
?>
<!DOCTYPE html>
<html>
<head>
<title>Dictionary!</title>
</head>
<body>
<?php
if(isset($_GET["word"])){
$word = $conn->real_escape_string(strtolower($_GET["word"]));
$sql = $conn->query("SELECT * FROM dictionary WHERE word=LOWER('".$word."') LIMIT 1");
if(!$sql){
echo "Sorry, something went wrong: ".$conn->error_get_last();
} else {
while($row=$sql->fetch_assoc()){
echo "<h2>".$row["word"]."</h2>";
echo "<p>".$row["definition"]."</p>";
}
}
} else {
$sql = $conn->query("SELECT word FROM dictionary");
if(!$sql){
echo "Sorry, something went wrong: ".$conn->error_get_last();
} else {
echo "<p>Here are all our words:</p><ul>";
while($row=$sql->fetch_assoc()){
echo "<li>".$row["word"]."</li>";
}
}
echo "</ul>";
}
?>
</body>
</html>
You should also take care to be consistent in your terminology. For this, my MySQL table had three columns: id, word, and definition. I dropped term since your URLs were using word. In my experience, it's best to keep the same terminology. It avoids confusion when your application gets more complicated.
Lastly, to answer your question about creating separate pages, you can see there that for a simple page like this, you may not need a separate page to display the definitions and the links -- just an if/else statement. If you want to expand what's in those if/else blocks, I'd suggest looking at PHP's include function.
You have a great start. Keep at it!

Echo out user information in the same table to their page base on their store information without echoing out the same information to another user

First of all I stored users in the same table and I created a page called welcome.php, where I want it to be echoing out user info from MySQL based on their entry.
Now when I created first user and echo it out to this welcome.php, it comes out from the table, and if I create another user info in the same table for it to echo out at the same welcome.php based on the user login info such as, if I create a user called John Fred etc and a user called Michael Kenneth etc.
So user John Fred comes out to the welcome.php with its information from the same table, and then user Michael Kenneth doesn't come to welcome.php when i sign with user Michael Kenneth instead it shows only user John Fred. I don't know where this error comes from; maybe from the login.php, or from welcome.php.
Here is my code echoing in welcome.php
<?php
$tnumber2 = "{$_SESSION['tnumber2']}";
// Connect to the database
$db = mysql_connect("$Sname","$Uname","$Pname") or die("Could not connect to the Database.");
$select = mysql_select_db("$Dname") or die("Could not select the Database.");
$sql="SELECT * FROM `$Tname` LIMIT 0, 25 ;";
$result=mysql_query($sql);
$rows=mysql_fetch_array($result);
?>
<? echo $rows['tnumber2']; ?>
Another script for other user info which I store for another table:
<?php
// Connect to the database
$tnumber2 = "{$_SESSION['tnumber2']}";
$db = mysql_connect("$Sname","$Uname","$Pname") or die("Could not connect to the Database.");
$select = mysql_select_db("$Dname") or die("Could not select the Database.");
$sql="SELECT * FROM `$UPname` LIMIT 0, 25 ;";
$result=mysql_query($sql);
?>
<?php
while($rows=mysql_fetch_array($result)){ // Start looping table row
?>
<? echo $rows['pdate']; ?>
<?php
// Exit looping and close connection
}
mysql_close();
?>
And here is my login.php in this case am using one input form:
<?php
session_start();
ob_start();
?>
<?php
if ($_POST['submit']) {
$tnumber2 = $_POST['user'];
if ($tnumber2) {
require("connect.php");
$query = mysql_query("SELECT * FROM users WHERE tnumber2='$tnumber2'");
$numrows = mysql_num_rows($query);
if($numrows == 1) {
$row = mysql_fetch_assoc($query);
$id = $row['id'];
$tnumber2 = $row['tnumber2'];
if ($tnumber2 == $tnumber2) {
$_SESSION['id'] = $id;
$_SESSION['tnumber2'] = $tnumber2;
header("Location: welcome.php");
}
}
else
include "error.php";
}
}
?>
I have tried all I can on this, maybe I might be a fool to think that such thing is possible but I am not a PHP professional, just a learner, please any help will be gladly appreciated.
Assuming the session has indeed stored the data of the logged-in user, you need to change "welcome.php" so it reads the correct user with a WHERE clause:
<?php
// Retrieve the ID of the user (and untaint it too)
$id = (int) $_SESSION['id'];
// Connect to the database (I've removed the unnecessary quotes)
$db = mysql_connect($Sname, $Uname, $Pname) or die("Could not connect to the Database.");
$select = mysql_select_db($Dname) or die("Could not select the Database.");
// Here is the query from the users table, we're selecting one user here
$sql="SELECT * FROM `users` WHERE `id` = $id;";
$result = mysql_query($sql);
$rows = mysql_fetch_array($result);
?>
<!-- Let's see what is in rows now, should be just one record -->
<?php print_r($rows) ?>
I would advise that you try to understand each part of the code above, and indeed the same for the code you have - don't just copy-and-paste without knowing what each bit does. If you get stuck on something, don't be afraid to look it up in the manual!
I've used print_r to just dump the row result - you can use the contents of that to determine what columns and other data you wish to extract out of it. After you have done that, the print_r can be removed.
Bear in mind that your login is not testing for password correctness - it only checks that someone has entered a particular username in login.php. If you want users to log on with a username and password, that needs to be designed and implemented as well. There are many questions on this site with best-practice techniques on how to do that, if that's of interest to you.
It has, incidentally, been rather difficult to understand what you are doing. I don't think this is a problem with your English, which seems fine to me. Rather, it's worth remembering to write in short sentences (no more than 20 words, say) and short paragraphs (no more than 4 or 5 sentences). And keep your descriptions as short as you can - it makes the difference between people helping you and their deciding they don't understand what you are trying to do. I expect this advice would be just as relevant in your native language as well!
Also, remember to add as much useful information to a question as you can, and if people ask for clarification, make sure you answer all their questions. Remember that people here are volunteers, and you need to make their job as easy as possible.

got stuck converting MySql output in JSON array with php

I am making an iphone app. a part of that app allows users to search for a company on location.
I have a MySql database containing the companies that can be searched for, and a php file on my website to receive the searched data, and to return the companyName and companyLocation for all the found companies to my app. it looks like this:
<?php
if (isset($_GET["companyCitySearchField"])){
$companyCity = $_GET["companyCitySearchField"];
$result = search($companyCity);
echo $result;
}
function makeSqlConnection()
{
$DB_HostName = "******";
$DB_Name = "*******";
$DB_User = "*******";
$DB_Pass = "*******";
$con = mysql_connect($DB_HostName,$DB_User,$DB_Pass) or die(mysql_error());
mysql_select_db($DB_Name,$con) or die(mysql_error());
return $con;
}
function disconnectSqlConnection($con)
{
mysql_close($con);
}
function search($companyCity)
{
$con = makeSqlConnection();
$query = mysql_query("SELECT companyName, companyCity from Company WHERE companyCity = '$companyCity'");
$companies = array();
while ($row = mysql_fetch_assoc($query)) {
$companies['companies'][] = $row;
print json_encode($companies);
}
disconnectSqlConnection($con);
}
?>
this works fine when only one company is found. it gives me a perfect JSON array:
{"companies":[{"companyName":"Dijkstra","companyCity":"Geldermalsen"}]}
everything fine so far.
Now, I create another company in my database, also with Geldermalsen as location.
2 companies are found in the database now. the JSON array it return now, doesn't make sense:
{"companies":[{"companyName":"Dijkstra","companyCity":"Geldermalsen"}]}{"companies":[{"companyName":"Dijkstra","companyCity":"Geldermalsen"},{"companyName":"testaccount","companyCity":"Geldermalsen"}]}
for some reason, it seems to make 2 separate array's. one for the first found company, and one with both.
I have been searching the web, stackoverflow, google and even the book 'PHP and MySql for dummies' for days, and I have changed my code numerous times, and whatever I try it keeps on doing this.
Does anyone know what I should do to get one array containing all found companies with this script, instead of these 2?
any help would be very welcome, Thank you in advance!
You are echoing out JSON for each row, not for the fully built array. Move your print statement outside the loop.
$companies = array();
while ($row = mysql_fetch_assoc($query)) {
$companies['companies'][] = $row;
}
print json_encode($companies);
Or better yet, you might not want to echo out anything at all in the search function, but leave that up to the caller. It seems you already might be intending to do this here:
$result = search($companyCity);
echo $result;
The only problem is that the search() function doesn't return any value so $result would be null. You should make up your mind about where you are going to echo the result to the client and be consistent about it.

PHP If Statements With mySQL Results

The code below is supposed to check if there is a person in the database with a row in the database with the username it gets from the cookie login.And if there is it is supposed to include a page and if there isn't a person in the database with this user_id it is supposed to echo.Here is my code so far please tell me how I would do this.I also already know before someone tells me that mySQL statements like I have it are becoming depreciated.Here is My code:
<?php
include("dbconnect.php");
mysql_select_db("maxgee_close2");
$username = $_COOKIE['maxgee_me_user'];
$result = mysql_query("select user_id from users where username = '$username'");
$row = mysql_fetch_array($result);
mysql_free_result($result);
$check = mysql_query("SELECT * FROM events_main WHERE user_id ='$row['user_id']'") or die(mysql_error());
if(1==1){
if (mysql_num_rows($check)>0)
{
include("example.php");
}
else
{
echo "example";
}
}
?>
In the double-quoted string, your array variable $row['user_id'] is being incorrectly parsed due to the fact that you have quoted the array key without surrounding the whole thing in {}. It is permissible to omit the {} in a double-quoted string if you don't quote the array key, but the {} adds readability.
check = mysql_query("SELECT * FROM events_main WHERE user_id ='{$row['user_id']}'") or die(mysql_error());
//-------------------------------------------------------------^^^^^^^^^^^^^^^^^^
// Also acceptable, but not as tidy, and troublesome with multidimensional
// or variable keys - unquoted array key
check = mysql_query("SELECT * FROM events_main WHERE user_id ='$row[user_id]'") or die(mysql_error());
//-------------------------------------------------------------^^^^^^^^^^^^^^^^^^
As mentioned above, $_COOKIE is never considered a safe value. You must escape its values against SQL injection if you continue to use the old mysql_*() API:
$username = mysql_real_escape_string($_COOKIE['maxgee_me_user']);
2 Things right off the bat, like Waleed said you're open to SQL injection, not very nice thing to have happen to you. I would look into reading tutorials about MySQLi and PDOs, from there try and dive into a better way or running queries.
Also you are choosing to use cookies instead of sessions to store the username? Cookies can be modified client-side to say anything a smart user with firebug would want them to be. Sessions are stored server-side and the client (end-user) is only given an id of the session. They cannot modify the username if you send it as a session. (They could try and change the session id to another random bunch of numbers but thats like pissing into the wind, pardon my french.
Heres some pseduo code that will get you on your way I think
<?php
include("dbconnect.php");
$database = "maxgee_close2"; //Set the database you want to connect to
mysql_select_db($database); //Select database
$username = $_SESSION['maxgee_me_user']; //Grab the username from a server-side stored session, not a cookie!
$query = "SELECT user_id FROM `users` WHERE `username` = '" . mysql_real_escape_string($username) . "' LIMIT 1"; //Note the user of mysql_real_escape_string on the $username, we want to clean the variable of anything that could harm the database.
$result = mysql_query($query);
if ($row = mysql_fetch_array($result)) {
//Query was ran and returned a result, grab the ID
$userId = $row["user_id"];
mysql_free_result($result); //We can free the result now after we have grabbed everything we need
$query_check = "SELECT * FROM `events_main` WHERE `user_id` = '" . mysql_real_escape_string($userId) . "'";
$check = mysql_query($query_check);
if (mysql_num_rows($check)>0) {
include("example.php");
}
else {
echo "example";
}
}
?>
That code may/may not work but the real key change is that fact that you were running
mysql_free_result($result);
before your script had a chance to grab the user id from the database.
All in all, I would really go back and read some more tutorials.

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