How to correctly fetch data to array with bind_params in PHP

Question

I am currently trying to execute some MySQL query and save the results into an array using bind_params for 2 params: userUniqueId (String) and limit (used to LIMIT query records) . I've tried to do sth on my own but seems the code does not work properly. I've tried different ways to do that but still nothing. Can you try to help me? Query works fine cause I've tested it in phpMyAdmin The function I want to write must fetch records into and array and then I would like to json_encode that array using that array as a result of the function.

Here is my function code:

public function getUserFavouriteRecipes($user_unique_id, $limit) {
    $stmt = $this->conn->prepare("SELECT recipe.`unique_id`, recipe.`title`, recipe.`img_tumbnail_link`, recipe.`add_date`, recipe.`kitchen_type`, recipe.`meal_type`, user.`name`, user.`surname`, 
                                    (SELECT count(*) from `like` WHERE recipe.`unique_id` = `like`.`recipe_unique_id_fk`) AS like_count 
                                    FROM `recipe` 
                                    JOIN `favourite` ON (recipe.`unique_id` = `favourite`.`recipe_unique_id_fk`) 
                                    JOIN `user` ON (recipe.`user_unique_id_fk` = user.`unique_id`) 
                                    WHERE favourite.`user_unique_id_fk` = ?
                                    ORDER BY recipe.`add_date` DESC
                                    LIMIT ?, 10");
    $converted_limit = intval($limit);                      

    $stmt->bind_param("si", $user_unique_id, $limit);   
    $result = $stmt->execute();

    if ($result) {
        $myArray = array();

        // Fetching Rows From Query
        while ($row = $result->get_result()->fetch()) {
            $myArray[] = $row;
        }
        $stmt->close();

        return $myArray;
    } else {
        return NULL;
    }
}

Here I try do encode it:

<?php
require_once 'include/DB_Functions.php';
$db = new DB_Functions();

// Receiving The Post Params
$user_unique_id = $_POST['user_unique_id_fk'];
$limit = $_POST['limit'];

// Getting Result Array
$resultArray = $db->getUserFavouriteRecipes($user_unique_id, $limit);
echo json_encode($resultArray);
?>

Thanks in advance for your help.

Answer 1

The correct way to fetch results using prepared statements is:

...    
$stmt->execute();
$myArr = array();
$tmp = array();
$stmt->bind_result($tmp['unique_id'], $tmp['title'], ...); // all fields in select
$i = 0;
while($stmt->fetch()) {
    $myArr[$i] = $tmp;
    $i++;
}
if (count($myArr) > 0) {
    return $myArr;
} else {
    return false;
}

Answer 2

You can use PDOStatement::fetchAll() to return an array containing all of the result set rows, like this:

public function getUserFavouriteRecipes($user_unique_id, $limit) {

    // your code

    $stmt->execute();
    return $stmt->fetchall(PDO::FETCH_ASSOC);
}

$resultArray = $db->getUserFavouriteRecipes($user_unique_id, $limit);

To encode the results you can do:

$json=json_encode($resultArray);

And if you want to display the results, you can do something like this:

//loop over the $resultArray, setting $result to an array representing each row
foreach($resultArray as $result){
    //loop over each $result (row), setting $key to the column name and $value to the value in the column.
    foreach($result as $key=>$value){
        //echo the key and value.
        echo "{$key} = {$value}<br>";
    }
}

Edited:

public function getUserFavouriteRecipes($user_unique_id, $limit) {

    // your code

    $status = $stmt->execute();

    $myArray = array();
    if($status){
        // Extract result set and loop rows
        $result_set = $stmt->get_result();

        while($result = $result_set->fetch_assoc()){
            $myArray[] = $result;
        }
        return $myArray;
    }else{
        return NULL;
    }

}

$resultArray = $db->getUserFavouriteRecipes($user_unique_id, $limit);
$json = json_encode($resultArray);

Your issue lies here:

The following illustrates the LIMIT clause syntax with two arguments:

SELECT 
    column1,column2,...
FROM
    table
LIMIT offset , count;

Let's examine the LIMIT clause parameters:

• The offset specifies the offset of the first row to return. The offset of the first row is 0, not 1.
• The count specifies maximum number of rows to return.

So the reason you're getting this string '[]' (length=2) result is because of the fact that it's not able to fetch any record based on your offset and count .

Try this:

public function getUserFavouriteRecipes($user_unique_id, $limit) {
    $stmt = $this->conn->prepare("SELECT recipe.`unique_id`, recipe.`title`, recipe.`img_tumbnail_link`, recipe.`add_date`, recipe.`kitchen_type`, recipe.`meal_type`, user.`name`, user.`surname`, 
                                    (SELECT count(*) from `like` WHERE recipe.`unique_id` = `like`.`recipe_unique_id_fk`) AS like_count 
                                    FROM `recipe` 
                                    JOIN `favourite` ON (recipe.`unique_id` = `favourite`.`recipe_unique_id_fk`) 
                                    JOIN `user` ON (recipe.`user_unique_id_fk` = user.`unique_id`) 
                                    WHERE favourite.`user_unique_id_fk` = ?
                                    ORDER BY recipe.`add_date` DESC
                                    LIMIT ?");
    $converted_limit = intval($limit);                      

    $stmt->bind_param("si", $user_unique_id, $converted_limit);   

    $status = $stmt->execute();

    $myArray = array();
    if($status){
        // Extract result set and loop rows
        $result_set = $stmt->get_result();

        while($result = $result_set->fetch_assoc()){
            $myArray[] = $result;
        }
        return $myArray;
    }else{
        return NULL;
    }
}

$resultArray = $db->getUserFavouriteRecipes($user_unique_id, $limit);
$json = json_encode($resultArray);
//var_dump($json);