I am new in PHP so I have to apologize for such a dumb question, but I am not sure how to find the right answer. I should check if my final result is empty (if $sql found anything). If it didnt find I would like to get some notification example "The list is empty". That message will also be visible from Android app when I call the url?
<?php
$host = "";
$user = "";
$pwd = "";
$db = "";
$con = mysqli_connect($host, $user, $pwd, $db);
if(mysqli_connect_errno($con)) {
die("Failed to connect to MySQL: " . mysqli_connect_error());
}
// query the application data
$sql = "SELECT * FROM lista WHERE Grad='".$_GET['grad']."' AND Predmet='".$_GET['predmet']."'";
$result = mysqli_query($con, $sql);
$rows = array();
while($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
$rows[] = $row;
}
mysqli_close($con);
echo json_encode($rows);
If mysqli_num_rows returns 0, you have no records.
$result = mysqli_query($con, $sql);
if (mysqli_num_rows($result) == 0) {
$rows = "no rows found";
} else {
$rows = array();
while($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
$rows[] = $row;
}
}
mysqli_close($con);
echo json_encode($rows);
Related
I'm having some troubles with fetching some database information with my php code.
All I'm getting is this message: "Connected successfully0 results".
Here's my code guys, thanks for the help in advance.
<?php
$servername = "example";
$username = "example1";
$password = "example2";
$row = array();
$conn = new mysqli($servername,$username,$password);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
$sql = "Select Distinct subject from mobile_math_science_toc";
$result = mysqli_query($conn, $sql);
if ($result = $conn->query($sql)) {
// output data of each row
while($row = mysqli_fetch_assoc($result)) {
echo "Subject " ,$row["subject"];
}
} else {
echo "0 results ";
}
mysqli_close($conn);
?>
You should add dbname while creating your connection to database. You can use mysqli_num_rows function to count no. of rows.
<?php
$servername = "example";
$username = "example1";
$password = "example2";
$dbname = "your_db_name"; // Specify your db-name here.
$conn = new mysqli($servername,$username,$password,$dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
$sql = "Select Distinct subject from mobile_math_science_toc";
$result = mysqli_query($conn, $sql);
// Checking if there are some records available.
if (mysqli_num_rows($result) > 0) {
// output data of each row
while($row = mysqli_fetch_assoc($result)) {
echo "Subject " ,$row["subject"];
}
} else {
echo "0 results ";
}
mysqli_close($conn);
?>
Change
$conn = new mysqli($servername,$username,$password);
To
$conn = new mysqli($servername,$username,$password, "<your database name>");
And
$result = mysqli_query($conn, $sql);
if ($result = $conn->query($sql)) {
}
To
$result = $conn->query($sql);
if ($result) {
}
Try
if (mysqli_num_rows($result) > 0) {
While checking you got the data or not
This my PHP URL for fetching the data from MySQL. I need to make mysqli_fetch_array code saying if filled uid in the app-data table is the same with uid in users table fetch the data from all row in app-data to the uid like every user show his items from app-data table.
$host = "";
$user = "";
$pwd = "";
$db = "";
$con = mysqli_connect($host, $user, $pwd, $db);
if(mysqli_connect_errno($con)) {
die("Failed to connect to MySQL: " . mysqli_connect_error());
}
$sql = "SELECT * FROM app_data ORDER By id";
$result = mysqli_query($con, $sql);
$rows = array();
while($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
$rows[] = $row;
}
mysqli_close($con);
echo json_encode($rows);
I think this is the correct answer:
<?php
$host = "";
$user = "";
$pwd = "";
$db = "";
$con = mysqli_connect($host, $user, $pwd, $db);
if(mysqli_connect_errno($con)) {
die("Failed to connect to MySQL: " . mysqli_connect_error());
}
$sql = "SELECT * FROM app_data WHERE u_id=".$_POST['posted_uid']." ORDER By id";
$result = mysqli_query($con, $sql);
$rows = array();
while($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
$rows[] = $row;
}
mysqli_close($con);
echo json_encode($rows);
Little tip for the future:
Don't search exactly what you want, only search in parts.
I have an issue with ajax response. I am using custom query for fetch result from database. Json response always shows null value while query is running successfully. Here is my code:
if(isset($_POST)){
$arr = array();
//$query = mysql_query(" insert into login (user,pass) values ('".$_POST['firstname']."','".$_POST['lastname']."') ") or die('test');
$query = mysql_query(" select * from login where user = '".$_POST['firstname']."' && pass = '".$_POST['pass']."' ") or die('test');
$rows = mysql_num_rows($query);
while($fetch = mysql_fetch_array($query))
{
if($fetch)
{
$_SESSION['ID']= $fetch['id'];
$arr['id'] = $_SESSION['ID'];
}
else
{
$arr['failed']= "Login Failed try again....";
}
}
echo json_encode($arr);
}
#Amandhiman i did not get what is the use of if statement with in the while
if($fetch)
{
$_SESSION['ID']= $fetch['id'];
$arr['id'] = $_SESSION['ID'];
}
the mention code definitely works for you
if($rows>0)
{
while($fetch = mysql_fetch_array($query))
{
$_SESSION['ID']= $fetch['id'];
$arr['id'] = $_SESSION['ID'];
}
}else
{
$arr['failed']= "Login Failed try again....";
}
Try with the below code, (mysql is deprected), working for me with my test database table (Debug it, var_dump $result, $result->fetch_assoc(), $result->num_rows)
<?php
$servername = "localhsot";
$username = "yourser";
$password = "passyour";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error)
die("Connection failed: " . $conn->connect_error);
if(isset($_POST)){
$arr = array();
$query = "select * from login where user = '".$_POST['firstname']."' && pass = '".$_POST['pass']."' ";
$result = $conn->query($query);
$rows = $result->num_rows;
while($fetch = $result->fetch_assoc())
{
if($fetch)
{
$_SESSION['ID']= $fetch['id'];
$arr['id'] = $_SESSION['ID'];
}
else
{
$arr['failed']= "Login Failed try again....";
}
}
echo json_encode($arr);
}
try this
if(isset($_POST)){
$arr = array();
//$query = mysql_query(" insert into login (user,pass) values ('".$_POST['firstname']."','".$_POST['lastname']."') ") or die('test');
$query = mysql_query(" select * from login where user = '".$_POST['firstname']."' && pass = '".$_POST['pass']."' ") or die('test');
$rows = mysql_num_rows($query);
if($rows>0)
{
while($fetch = mysql_fetch_array($query))
{
$_SESSION['ID']= $fetch['id'];
$arr['id'] = $_SESSION['ID'];
}
}else
{
$arr['failed']= "Login Failed try again....";
}
echo json_encode($arr);
}
First of all start session before playing with it on the top of page
session_start();
check your database connectivity.
Use print_r($arr) for testing your array();
first off all you are using session variable . to use session variable you need to initialize it by session_start()
you are using key in the array in this way it will return the last inserted record in the array . try this code
<?php
$servername = "localhsot";
$username = "yourser";
$password = "passyour";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error)
die("Connection failed: " . $conn->connect_error);
if(isset($_POST)){
$arr = array();
$query = "select * from login where user = '".$_POST['firstname']."' && pass = '".$_POST['pass']."' ";
$result = $conn->query($query);
$rows = $result->num_rows;
while($fetch = $result->fetch_assoc())
{
if($fetch)
{
// if wants to use session then start session
session_start(); // else it will return null
$_SESSION['ID']= $fetch['id']; // i don't know why this ??
// $arr['id'] = $_SESSION['ID']; comment this
$arr[] = array('msg'=>'succsee','ID'=>$fetch['id']);
}
else
{
$arr[]= array('msg'=>'fail','ID'=>null);
}
}
echo json_encode($arr);
}
I recently started updating some code to MySQL improved extension, and have been successful up until this point:
// old code - works
$result = mysql_query($sql);
if(mysql_num_rows($result) == 1){
$row = mysql_fetch_array($result);
echo $row['data'];
}
// new code - doesn't work
$result = $mysqli->query($sql) or trigger_error($mysqli->error." [$sql]");
if($result->num_rows == 1) {
$row = $result->fetch_array();
echo $row['data'];
}
As shown I am trying to use the object oriented style.
I get no mysqli error, and vardump says no data... but there definitely is data in the db table.
Try this:
<?php
// procedural style
$host = "host";
$user = "user";
$password = "password";
$database = "db";
$link = mysqli_connect($host, $user, $password, $database);
IF(!$link){
echo ('unable to connect to database');
}
ELSE {
$sql = "SELECT * FROM data_table LIMIT 1";
$result = mysqli_query($link,$sql);
if(mysqli_num_rows($result) == 1){
$row = mysqli_fetch_array($result, MYSQLI_BOTH);
echo $row['data'];
}
}
mysqli_close($link);
// OOP style
$mysqli = new mysqli($host,$user, $password, $database);
$sql = "SELECT * FROM data_table LIMIT 1";
$result = $mysqli->query($sql) or trigger_error($mysqli->error." [$sql]"); /* I have added the suggestion from Your Common Sence */
if($result->num_rows == 1) {
$row = $result->fetch_array();
echo $row['data'];
}
$mysqli->close() ;
// In the OOP style if you want more than one row. Or if you query contains more rows.
$mysqli = new mysqli($host,$user, $password, $database);
$sql = "SELECT * FROM data_table";
$result = $mysqli->query($sql) or trigger_error($mysqli->error." [$sql]"); /* I have added the suggestion from Your Common Sence */
while($row = $result->fetch_array()) {
echo $row['data']."<br>";
}
$mysqli->close() ;
?>
As it was said, you're not checking for the errors.
Run all your queries this way
$result = $mysqli->query($sql) or trigger_error($mysqli->error." [$sql]");
if no errors displayed and var dumps are saying no data - then the answer is simple: your query returned no data. Check query and data in the table.
In PHP v 5.2 mysqli::num_rows is not set before fetching data rows from the query result:
$mysqli = new mysqli($host,$user, $password, $database);
if ($mysqli->connect_errno) {
trigger_error(sprintf(
'Cannot connect to database. Error %s (%s)',
$mysqli->connect_error,
$mysqli->connect_errno
));
}
$sql = "SELECT * FROM data_table";
$result = $mysqli->query($sql);
// a SELECT query will generate a mysqli_result
if ($result instanceof mysqli_result) {
$rows = array();
while($row = $result->fetch_assoc()) {
$rows[] = $row;
}
$num_rows = $result->num_rows; // or just count($rows);
$result->close();
// do something with $rows and $num_rows
} else {
//$result will be a boolean
}
$mysqli->close() ;
The following code always displays
rows = 0
eventhough the table contains Ravi in the field 'to'. Does anyone know what is wrong with this code?
<?php
$response = array();
$con = mysql_connect("localhost","root","");
if(!$con) {
die('Could not connect: '.mysql_error());
}
mysql_select_db("algopm1",$con);
//if (isset($_POST['to'])) {
$to = "Ravi";
$result = mysql_query("SELECT *FROM `events` WHERE to = '$to'");
if (!empty($result)) {
if (mysql_num_rows($result)>0) {
$result = mysql_fetch_array($result);
echo $result["to"] + " " + $result["from"];
} else {
echo 'rows = 0';
}
} else {
echo 'empty for Ravi';
}
//} else {
//}
?>
to is a reserved word in MySQL, if you want to use it you must encase it in backticks:
.... WHERE `to` = ...
I have not look at your code but I recommend looking at
http://php.net/manual/en/intro.mysql.php
this before you continue to use mysql and not mysqli. It isn't that different but mysqli seems to have a wrapper over mysql and uses the "->" to instantiate new classes for a connection. If that makes any sense.
Try this:
<?php
$response = array();
$con = mysql_connect("localhost","root","");
if(!$con) {
die('Could not connect: '.mysql_error());
}
mysql_select_db("algopm1",$con);
//if (isset($_POST['to'])) {
$to = "Ravi";
$result = mysql_query("SELECT *FROM `events` WHERE `to` = '$to'");
if (!empty($result)) {
if (mysql_num_rows($result)>0) {
$row = mysql_fetch_array($result);
echo $row["to"] + " " + $row["from"];
} else {
echo 'rows = 0';
}
} else {
echo "empty for $to";
}
//} else {
//}
?>
MYSQLI version + some adjustments:
<?PHP
$host = "localhost";
$user = "root";
$password = "";
$database="algopm1";
$link = mysqli_connect($host, $user, $password, $database);
IF (!$link){
echo ("Unable to connect to database!");
}
ELSE {
$query = "SELECT *FROM `events` WHERE `to` = '$to'";
$result = mysqli_query($link, $query);
if (mysql_num_rows($result)>0) {
while($row = mysqli_fetch_array($result, MYSQLI_BOTH)){
echo $row["to"]. "+". $row["from"];
}
}
ELSE {
echo 'rows = 0';
}
}
mysqli_close($link);
?>
I would like to credit #njk and #Wezy for their contribution with regard to the reserved word to in mysql. The WHILE loop is not necessary if the table events can only contain one "to" in this case "Ravi". I suspect that the number of events can be greater than one.
#Wezy has a point but let's do the troubleshooting:
As #JonathanRomer in his comment suggested, do:
$result = mysql_query("SELECT *FROM `events` WHERE `to` = '$to'") or die(mysql_error());
What does it say? Does it fail at all?
Or, just before mysql_query do:
die("SELECT *FROM `events` WHERE `to` = '$to'");
this will print faulty query being executed. Next, fire up mysql console or PHPMyAdmin and try executing this query manually.
Again, what does it say?
Actually, my main purpose was to encode this message and receive it on a mobile device by using JSON. This is the full code. For normal checking purpose, instead of using json_encode(*), the values can be displayed individually. This is the solution I got and it is working perfectly for receiving the data in an android app on which I am working.
<?php
$host = "localhost";
$user = "root";
$password = "";
$database="algopm1";
$response = array();
$mysqli = new mysqli($host, $user, $password, $database);
if (mysqli_connect_errno()){
$response["success"] = 0;
$response["message"] = mysqli_connect_error();
echo json_encode($response);
}
if(isset($_POST['to'])) {
$to = $_POST['to'];
$query = "SELECT *FROM `events` WHERE `to` = '$to'";
if($stmt = $mysqli->prepare($query)) {
$stmt->execute();
$stmt->store_result();
$i = 0;
if($stmt->num_rows > 0) {
$stmt->bind_result($rowto, $rowfrom, $rowevent);
$response["events"] = array();
while($stmt->fetch()) {
$events = array();
$events["to"] = $rowto;
$events["from"] = $rowfrom;
$events["event"] = $rowevent;
array_push($response["events"], $events);
}
$response["success"] = 1;
echo json_encode($response);
} else {
$response["success"] = 0;
$response["message"] = "No events found";
echo json_encode($response);
}
$stmt->close();
}
} else {
$response["success"] = 0;
$response["message"] = "Required fields are missing";
echo json_encode($response);
}
$mysqli->close();
?>