I have the following code to check if a row exists in MySQL:
<?php
if (!empty($_POST)) {
$code = $_POST['code'];
mysql_connect("$dbhost","$dbuser","$dbpass");
mysql_select_db("$dbname");
$result = mysql_query("SELECT 1 FROM files WHERE id='$code' LIMIT 1");
if (mysql_fetch_row($result)) {
echo 'Exists';
} else {
echo 'Does not exist';
}
}
?>
This works fine. But I need to change it a bit. I have the following fields:
id, title, url, type. When someone uses the code above ^ to check if a row exists, I need a variable to get the url from the same row, so I can redirect the user to there.
Do you have any idea how I can do that?
Thanks in advance! :)
Try this:
<?php
if (!empty($_POST)) {
$code = $_POST['code'];
mysql_connect("$dbhost","$dbuser","$dbpass");
mysql_select_db("$dbname");
$result = mysql_query("SELECT * FROM files WHERE id=" . $code . " LIMIT 1");
if (mysql_num_rows($result) > 0) {
while($rows = mysql_fetch_array($result)) {
echo 'Exists';
$url = $rows['url'];
}
} else {
echo 'Does not exist';
}
}
?>
It is quite simple. I think you don't show any effort to find the solution by yourself.
<?php
if (!empty($_POST)) {
$code = $_POST['code'];
mysql_connect("$dbhost","$dbuser","$dbpass");
mysql_select_db("$dbname");
$result = mysql_query("SELECT url FROM files WHERE id='$code' LIMIT 1");
if ($result) {
$url = mysql_fetch_row($resultado);
} else {
echo 'Does not exist';
}
}
<?php
$sql_query = "SELECT * FROM test WHERE userid ='$userid'";
$result1 =mysql_query($sql_query);
if(mysql_num_rows($result1)>0){
while($post = mysql_fetch_array($result1))
{
$url = $post['url'];
}
}
?>
If mysql_num_rows($result1)>0 it means row is existed fir the given user id
Related
I have a very simple use case where I am checking if a certain value is present in the table and it always seems to fail.This is my php code.
<?php
include "config.php";
$con = mysqli_connect($server_name,$mysql_user,$mysql_pass,$dbname);
if(!$con)
{
echo "Connection Error".mysqli_connect_error();
}
else{
//echo "";
}
$device_id = $_POST["device_id"];
$check = "SELECT magazine_id FROM registered_buyers WHERE device_id = $device_id";
$rs = mysqli_query($con,$check);
if(mysqli_num_rows($con,$rs) == 0)
{
$jsonarray = $_POST["jsonarray"];
echo "This will be inserted".$jsonarray;
}else
{
echo "User already registered";
}
?>
Can anyone please point out my mistake.Any help or suggestion is welcome.Thank you.
You can try to follow this code.
<?php
include "config.php";
$con = mysqli_connect($server_name,$mysql_user,$mysql_pass,$dbname);
if(!$con){
echo "Connection Error".mysqli_connect_error();
}
$device_id = $_POST["device_id"];
$check = "SELECT magazine_id FROM registered_buyers WHERE device_id = ".$device_id;
$rs = mysqli_query($con, $check);
if(mysqli_num_rows($rs) == 0){
$jsonarray = $_POST["jsonarray"];
echo "This will be inserted".$jsonarray;
}else{
echo "User already registered";
}
?>
since i dont have enough rep to add a comment, i will consider the device_id is string, if so try something like this:
"SELECT magazine_id FROM registered_buyers WHERE device_id = '$device_id'";
add '
I have a column called favid. I am trying to pull and compare the data in that column to an existing value:
<?php $query = mysql_query("SELECT * FROM ajaxfavourites WHERE favid=$favid");
while ($row = mysql_fetch_assoc($query)) {
echo $row['favid']; };?>
I also have an existing value:
$x
But when I do something like this it doesn't work:
<?php if($row['favid'] == $x){?>
Do this...
<?php } else { ?>
Do nothing...
<?php}?>
I realize the data in the column somehow isn't pulled out. What should be done for this to work?
Try this, I assume you already connected to DB.
<?php
$x = 1;
$query = mysql_query("SELECT * FROM ajaxfavourites WHERE favid='$favid'") or die(mysql_error());
if (mysql_num_rows($query) > 0)
{
while ($row = mysql_fetch_assoc($query))
{
if ($row["existing_column_name"] == $x)
{
echo "Yes";
} else
{
echo "No";
}
}
} else
{
echo "Nothing was found";
}
?>
<?php
$x = 100500; // integer for example
$CID = mysql_connect("host","user","pass") or die(mysql_error());
mysql_select_db("db_name");
$query = mysql_query("SELECT * FROM ajaxfavourites WHERE favid='{$favid}'", $CID);
while ($row = mysql_fetch_assoc($query)) {
if (intval($row["some_existing_column_name"])==$x){
print "Is equals!";
} else {
print "Is different!";
}
}
?>
Please be informed that mysql_connect and other functions with the prefix of mysql_ is deprecated and can be removed in the next versions of PHP.
i have the following information displayed
<?php
$my_query="SELECT * FROM games";
$result= mysqli_query($connection, $my_query);
if (mysqli_num_rows($result) > 0)
while ($myrow = mysqli_fetch_array($result))
{
$description = $myrow["game_description"];
$image = $myrow["gamepic"];
$game_id = $myrow["game_id"];
$gamename = $myrow["game_name"];
echo "<div class='cover'>
</div>";
}
?>
as you can see i have created a game_details page which will display that specific Game_id when the image is clicked
im having trouble understanding how to pull the data out from that game_id in sql on the other page.
here is my attempt on the game_details page
<?php
if (!isset($_GET['$game_id']) || empty($_GET['game_id']))
{
echo "Invalid category ID.";
exit();
}
$game_id = mysqli_real_escape_string($connection, $_GET['game_id']);
$sql1 = "SELECT * games WHERE game_id={$game_id}'";
$res4 = mysqli_query($connection, $sql1);
if(!$res4 || mysqli_num_rows($res4) <= 0)
{
while ($row = mysqli_fetch_assoc($res4))
{
$gameid = $row['$game_id'];
$title = $row['game_name'];
$descrip = $row['game_description'];
$genre = $row['genretype'];
echo "<p> {$title} </p>";
}
}
?>
This attempt is giving me the "invalid category ID" error
Would appreciate help
There are a few issues with your code.
Let's start from the top.
['$game_id'] you need to remove the dollar sign from it in $_GET['$game_id']
Then, $row['$game_id'] same thing; remove the dollar sign.
Then, game_id={$game_id}' will throw a syntax error.
In your first body of code; you should also use proper bracing for all your conditional statements.
This one has none if (mysqli_num_rows($result) > 0) and will cause potential havoc.
Rewrites:
<?php
$my_query="SELECT * FROM games";
$result= mysqli_query($connection, $my_query);
if (mysqli_num_rows($result) > 0){
while ($myrow = mysqli_fetch_array($result))
{
$description = $myrow["game_description"];
$image = $myrow["gamepic"];
$game_id = $myrow["game_id"];
$gamename = $myrow["game_name"];
echo "<div class='cover'>
</div>";
}
}
?>
Sidenote for WHERE game_id='{$game_id}' in below. If that doesn't work, remove the quotes from it.
WHERE game_id={$game_id}
2nd body:
<?php
if (!isset($_GET['game_id']) || empty($_GET['game_id']))
{
echo "Invalid category ID.";
exit();
}
$game_id = mysqli_real_escape_string($connection, $_GET['game_id']);
$sql1 = "SELECT * games WHERE game_id='{$game_id}'";
$res4 = mysqli_query($connection, $sql1);
if(!$res4 || mysqli_num_rows($res4) <= 0)
{
while ($row = mysqli_fetch_assoc($res4))
{
$gameid = $row['game_id'];
$title = $row['game_name'];
$descrip = $row['game_description'];
$genre = $row['genretype'];
echo "<p> {$title} </p>";
}
}
?>
Use error checking tools at your disposal during testing:
http://php.net/manual/en/mysqli.error.php
http://php.net/manual/en/function.error-reporting.php
You want to be using $_GET['gameid'] as that's the parameter you passed.
You are calling for game_id when the link to go to game_details.php has the variable gameid. Either change the parameter in the link to game_id or call for gameid in your $_GET['$game_id'].
Also, as Fred -ii- said, take out the dollar sign in $_GET['$game_id']
Code:
$Username = $_SESSION['VALID_USER_ID'];
$q = mysql_query("SELECT * FROM `article_table`
WHERE `Username` = '$Username'
ORDER BY `id` DESC");
while($db = mysql_fetch_array($q)) { ?>
<?php if(!isset($db['article'] && $db['subject'])) {
echo "Your articles";
} else {
echo "You have no articles added!";
} ?>
<?php } ?>
So I want the rows for example(db['article'] and $db['subject']) from a specific username (see: $Username = $_SESSION['VALID_USER_ID'];) to echo the information if is not empty else if is empty to echo for example "You have no articles added!"
If is some information in the rows the code works, echo the information BUT if the rows is empty don't echo nothing, the code should echo "You have no articles added!" but this line don't appear, where is the mistake?
I tried for if !isset, !empty, !is_null but don't work.
I think what you're trying to achieve is:
$Username = $_SESSION['VALID_USER_ID'];
$q = mysql_query("SELECT * FROM `article_table` WHERE `Username` = '$Username' ORDER BY `id` DESC");
if(mysql_num_rows($q) > 0)
{
echo "Your articles:\n";
while($db = mysql_fetch_array($q)) {
echo $db['subject']." ".$db['article']."\n";
}
}
else
{
echo "You have no articles added!";
}
?>
I don't understand. Do you have article rows with username, but without article, i.e.:
| id | user | article |
-------------------------------------
| 1 | X | NULL |
If so, you can test with:
if($db['article'] == NULL) { .... } else { .... }
Otherwise, if you don't have a row with user=x, when there are no record, mysql will return an empty result.
So, basicly, if no rows are found on selection: SELECT * FROM article_table WHERE Username = 'X';, you can test
if(mysql_num_rows($q) > 0) { .... } else { .... }
However, mysql_ functions are not recommended anymore. Look at prepared statements.
You have a logic error in your if statement -- what you want is to check if both the article and subject are set.
With your current code, you compare $db['article'] with $db['subject'], and check if the result is set. You need to change it a bit :
Instead of :
if(!isset($db['article'] && $db['subject'])) {
Try:
if(isset($db['article']) && isset($db['subject'])) ...
I would do something like this:
$articles='';
$Username = $_SESSION['VALID_USER_ID'];
$q = mysql_query("SELECT * FROM `article_table` WHERE `Username` = '$Username' ORDER BY `id` DESC");
while($db = mysql_fetch_array($q)) {
if(isset($db['article']) && isset($db['subject'])) {
$articles .= $db['article']."<br/>";
}
}
if($articles != ''){
echo $articles;
}
else{
echo "No articles";
}
?>
fastest way to achieve what you want is by adding a variable that will verify if the query returned any rows:
<?php $Username = $_SESSION['VALID_USER_ID'];
$i = 0;
$q = mysql_query("SELECT * FROM `article_table` WHERE `Username` = '$Username' ORDER BY `id` DESC");
while($db = mysql_fetch_array($q)) {
$i = 1;
if(!isset($db['article'] && $db['subject'])) { echo "Your articles"; } ?>
<?php }
if ($i == 0) echo "You have no articles";
?>
You tried to echo "no articles" in the while loop, you get there only if the query returns information, that is why if it returns 1 or more rows, $i will become 1 else it will remain 0.
In your case:
$numArticles = mysql_num_rows($q);
if($numArticles > 0)
echo 'Your articles';
else
echo 'No articles :((((';
I recommend tough moving on to PDO to communicate with DB.
I need to print a message if the $_GET[id] is not in database or do this code:
Header('Location:index.php');
Example:
If the people enter in this URL: /index.php?id=100
if there is no page "100" do:
Header('Location:index.php');
Roughly:
<?php
$imageid = (isset($_GET['img_id']) && is_numeric($_GET['img_id'])) ? (int)$_GET['img_id'] : false;
if ($imageid) {
$sql = "SELECT * FROM images WHERE imageid='$imageid';";
$result = mysql_query($sql);
if ($result) {
// imageid exists
my_image_display_function($result);
} else {
// imageid does not exist
header("Location: index.php");
}
}
?>
Update: Edited to more closely match OP's table/variable names.