Alternate Way to Check Result num_rows >0 - php

Up to now I was checking num_rows >0 the following way:
$sql = "SELECT name FROM tbl_criteria WHERE ID =?";
$stmt = mysqli_stmt_init($conn);
if(!mysqli_stmt_prepare($stmt, $sql)){
header("location: /XX");
}else{
mysqli_stmt_bind_param($stmt, "i", $cId);
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);
mysqli_fetch_all($result,MYSQLI_ASSOC);
if($result-> num_rows >0{
echo 'Appear if rows >0';
foreach($result as $row){
echo 'Appear for each result';
}
}
}
So suddenly this is not working anymore. I always get 0 results. I have read that it is important to call mysqli_stmt_store_result() before accessing num_rows otherwise it would usually return 0. I thought that I'm storing the results with $result = mysqli_stmt_get_result($stmt); or am I wrong?
I am hosting my website on a webserver so it could be because of an update as well. A couple of days ago it was working fine.

Your code is not working most likely due to multiple syntax errors you have. I recommend to read How to get the error message in MySQLi?
If you would like to continue using mysqli, then there is no need for this overly complex code. You can simply fetch all results into an array. There's no need to ever use num_rows.
$value = "cId";
$stmt = $conn->prepare("SELECT name FROM tbl_criteria WHERE ID =?");
$stmt->bind_param('s', $value);
$stmt->execute();
$result = $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
// If no rows were fetched the array will be empty and condition will be false
if ($result) {
echo 'Appear if rows >0';
foreach ($result as $row) {
echo 'Appear for each result';
}
}

Related

Why can't I get data from SQL row using PHP prepared statements?

Connection is good. I can insert into the database, and check if a row exists by checking if results > 0, but I can not select row data. The $email's being tested are in the database.
Ex 1.
require 'connection/connection.php';
$email = "sample#sample.com";
$sql = "SELECT * FROM users WHERE user_email=?"; // SQL with parameters
$stmt = $conn->prepare($sql);
$stmt->bind_param("s", $email);
$stmt->execute();
$result = $stmt->get_result(); // get the mysqli result
$user = $result->fetch_assoc(); // fetch data
echo $user['user_name'];
Ex. 2
$email = "james#james.com";
$sql = "SELECT * FROM users WHERE user_email=?";
$stmt = mysqli_stmt_init($conn);
mysqli_stmt_bind_param($stmt, "s", $email);
mysqli_stmt_execute($stmt);
After inserting an echo after every line one by one, this is as far as it gets. If an echo statement is placed after the next line it will not appear.
$result = mysqli_stmt_get_result($stmt);
if ($row = mysqli_fetch_assoc($result)) {
$_SESSION['active_user_id'] = $row['user_id'];
} else {
header("Location: https://example.com/");
exit();
}
The problem was fixed through cPanel. I had to switch from "mysqli" to "nd_mysqli." This fixed the problem right away.
I found the instructions to do this here https://www.plus2net.com/php_tutorial/mysqli_mysqlnd.php
I hope this helps others with the same problem.

why iam getting an error related to bind_result in error_log file and how to fix it? [duplicate]

This question already has answers here:
mysqli_stmt::bind_result(): Number of bind variables doesn't match number of fields in prepared statement
(2 answers)
Closed 1 year ago.
Iam getting this error
[07-Sep-2017 11:48:47 UTC] PHP Warning: mysqli_stmt::bind_result():
Number of bind variables doesn't match number of fields in prepared
statement
$stmt = $con->prepare("SELECT * FROM table where Id =?");
$stmt->bind_param("s", $_POST['Id']);
$stmt->execute();
$result = $stmt-> bind_result($Id);
$numRows = $result->num_rows;
if($numRows > 0) {
if($row = $result->fetch_assoc())
{
$Taxname=$row['TaxName'];
$Tid=$row['Id'];
}}
You need to alter your query. Instead of * you need to instead opt for picking out the data you actually want from the database.
For example, if the table table has columns Id,TaxName then you would execute like so:
<?php
$sqlData = array();
$stmt = $con->prepare("SELECT Id,TaxName FROM table where Id =?");
$stmt->bind_param("i", $_POST['Id']); //id is an integer? this should be i instead of s
$stmt->execute();
$stmt->store_result(); //store the result, you missed this
$stmt-> bind_result($Id,$TaxName); //bind_result grabs the results and stores in a variable
$numRows = $stmt->num_rows; //see the correction I made here
if($numRows >0){
while ($stmt->fetch()) { //propper way of looping thru the result set
$sqlData [] = array($Id,$TaxName);
//assoc array would look like:
//$sqlData [] = array("Id" =>$Id,"TaxName" => $TaxName);
}
}
$stmt->close(); //close the connection
?>
Then you would have an array of results that you can use after you've finished with mysqli queries.
Hope this helps you understand it a bit more.
$stmt = $con->prepare("SELECT Id,TaxName FROM table where Id =?");
$stmt->bind_param("s", $_POST['Id']);
$stmt->execute();
$result = $stmt-> bind_result($Id,$TaxName);
$stmt->store_result();
$numRows = $stmt->num_rows;
if($numRows > 0) {
while( $result->fetch_assoc())
{
$newid = $Id;
$newtaxname= $TaxName;
}
print_r($newid)."<br>";
print_r($newtaxname);
}
This code will give you the answer without any warnings.
Reference : http://php.net/manual/en/mysqli-stmt.bind-result.php
mysqli_stmt::bind_result — Binds variables to a prepared statement for
result storage

MySQLi Prepared Statement Query Results in an Array

Trying to transition over my old mysql queries to mysqli prepared statements. I've got everything figured out except for one thing. How can I get the query results stored as an array? I used to do this like this:
$sql = "SELECT * FROM Users";
$result = mysql_query($sql);
while ($row = mysql_fetch_array($result) {
// do stuff
}
Now I have the following code. In this case, my array is a single record, so I don't need to iterate over it, but I want to hold it as an array so that I can refer to its field names. Also, I will have other queries that will return multiple records, so I'll need to iterat then.
$sql = "SELECT * FROM Users
WHERE (LOWER(first_name)=LOWER(?) && LOWER(last_name)=LOWER(?))";
$stmt = mysqli_stmt_init($link);
$this_user;
if (mysqli_stmt_prepare($stmt, $sql)) {
/* Bind the input parameters to the query */
mysqli_stmt_bind_param($stmt, 'ss', $first_name, $last_name);
/* execute query, store results in an array */
mysqli_stmt_execute($stmt);
$result = mysqli_fetch_array($stmt);
if (mysqli_num_rows($result) == 0) {
mysqli_stmt_close($stmt);
mysqli_close($link);
$tag_result = "failure";
$tag_message = "No matching user found";
echo encodeJSONObj($tag_result, $tag_message);
die();
}
if (mysqli_num_rows($result) > 1) {
mysqli_close($link);
$tag_result = "failure";
$tag_message = "Multiple records found for this user.";
echo encodeJSONObj($tag_result, $tag_message);
die();
}
$this_user = mysqli_fetch_array($result);
/* close statement */
mysqli_stmt_close($stmt);
}
$id = $this_user['id'];
$first_name = $this_user['first_name'];
$last_name = $this_user['last_name'];
// and so on...
Can somebody tell me what I am doing wrong? Thanks!
EDIT: With big thanks to Phil, I've modified my code. However, I still seem to be returning 0 rows even though my input parameters should return exactly 1 row. Here is what I have:
$sql = "SELECT id, first_name, last_name, group_id, email, cell
FROM Users
WHERE (first_name=? && last_name=?)";
$stmt = mysqli_stmt_init($link);
if (mysqli_stmt_prepare($stmt, $sql)) {
/* Bind the input parameters to the query */
mysqli_stmt_bind_param($stmt, 'ss', $first_name, $last_name);
/* execute query, bind result, and fetch value */
mysqli_stmt_execute($stmt);
mysqli_stmt_bind_result($stmt, $id, $first_name, $last_name, $group_id, $email, $cell);
mysqli_stmt_fetch($stmt);
if (mysqli_stmt_num_rows($stmt) == 0) {
mysqli_stmt_close($stmt);
mysqli_close($link);
echo "No results returned";
die();
}
...
}
This always outputs No results returned when it should find 1 row and skip right past that block. I've been staring at this for a long time, but I just can't see what I am doing wrong.
Your script contains numerous errors (as mentioned in comments above). Here's a simple step-by-step...
Prepare a statement and bind parameters
$stmt = $link->prepare($sql);
if (!$stmt) {
throw new Exception($link->error, $link->errno);
}
// you can error check this too but it rarely goes wrong
$stmt->bind_param('ss', $first_name, $last_name);
Execute the statement and store the result
if (!$stmt->execute()) {
throw new Exception($stmt->error, $stmt->errno);
}
$stmt->store_result();
Do your number of row checks against $stmt->num_rows...
if ($stmt->num_rows == 0) {
// ...
}
if ($stmt->num_rows > 1) {
// ...
}
Bind and fetch the result
// This relies on the SELECT column ordering.
// You should probably change your SELECT statement to
// SELECT id, first_name, last_name FROM Users...
$stmt->bind_result($id, $first_name, $last_name);
$stmt->fetch();
$stmt->close();
$link->close();
If you want to fetch the single result row as an associative array, try this instead
$result = $stmt->get_result(); // note - this requires the mysqlnd driver
$this_user = $result->fetch_array(MYSQLI_ASSOC);
$result->free();
$stmt->close();
$link->close();

mysqli returning null values

im trying to get data from my DB but all i get is null values.
I know that the query isnt empty because i get values from inside my if($stmt->num_rows > 0)
code.
When i run my query on my phpmyadmin i also get good results.
This is my code thanks for helping:
$sql = "SELECT register_date FROM personal WHERE user_id = ?";
$stmt = $mysqli->prepare($sql) or trigger_error($mysqli->error."[$sql]");
$stmt->bind_param('s', $user_id);
$user_id = $_GET['user_id'];
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($register_date);
if($stmt->num_rows > 0)
{
$response["date"] = $register_date;
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
}
else
{
$response["success"] = 0;
echo json_encode($response);
}
Try
$stmt->bind_result($register_date);
$stmt->execute();
$stmt->store_result();
$stmt->fetch();
echo $register_date;
Please read bind_result doc
Your code is a bit mixed up, you'll need to define your variables (in this case $user_id) before using them.
I suggest moving to PDO rather than using MySQLi.

mysqli_stmt_num_rows() returns 0 rows

I tried to count return rows from a query using prepared statements.
Something like this :
$q = "SELECT name, address, contact FROM members";
$stmt = mysqli_prepare ($dbc, $q);
mysqli_stmt_store_result($stmt);
// Get the number of rows returned:
$rows = mysqli_stmt_num_rows($stmt);
echo $rows;
But always I am getting 0 rows when executing this query. I tested it using mysql client ant then I got 6 returned rows.
can anyone tell me what is the wrong with this?
Thank you.
You need to call mysqli_stmt_execute to actually get a result set, before trying to store the results.
$stmt = mysqli_prepare ($dbc, $q);
mysqli_stmt_execute($stmt); // <--------- currently missing!!!
mysqli_stmt_store_result($stmt);
$rows = mysqli_stmt_num_rows($stmt);
You have to execute the query
$q = "SELECT name, address, contact FROM members";
if ($stmt = mysqli_prepare ($dbc, $q)) {
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
// Get the number of rows returned:
$rows = mysqli_stmt_num_rows($stmt);
echo $rows;
mysqli_stmt_free_result($stmt);
mysqli_stmt_close($stmt);
}
You need to call execute() on your statement handle, right now you are only preparing the query.
$q = "SELECT name, address, contact FROM members";
$stmt = mysqli_prepare ($dbc, $q);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
// Get the number of rows returned:
$rows = mysqli_stmt_num_rows($stmt);
echo $rows;
i was concerned whether your table Members actually had records in it. Anyways try
$rows = mysqli_num_rows($stmt);
//or
$rows = mysql_num_rows($stmt);
This has worked out for me and has returned 5 as there were only 5 records in my table.

Categories