data of separate PHP array with comma

Question

based on a query:

  $query = $db->query("SELECT id, email, status, enviados FROM 
  contactos LIMIT 0,500");

where I get emails and store them in an array I want to separate them and print them by commas and then put them in a variable, where the result is something like:

$ variable = a1, a2, a3;

I try to do with implode but it does not work, I was already seeing the other issues but I can not find a solution

this is my code

$query = $db->query("SELECT id, email, status, enviados FROM 
contactos LIMIT 0,500");

$count = $query->num_rows;


while($row = mysqli_fetch_array($query)){
    $datos_seleccionados[] = array(
        'emails' => $row['email']
    );
}   

for ($i = 0; $i <= $count; $i++) {
    echo implode(",", $datos_seleccionados[$i]);
}

Answer 1

You need to do it in this way

$datos_seleccionados = [];
while($row = mysqli_fetch_array($query))
{
  $datos_seleccionados[] = $row['email'];
}
echo implode(",", $datos_seleccionados);

Answer 2

You can use array_column for this:

example code:

$data = [
    ['title' => 'foo', 'val' => 1],
    ['title' => 'bar', 'val' => 5],
    ['title' => 'foobar', 'val' => 9]
];

echo implode(',', array_column($data, 'val'));

here we just group the elements by the key (in this case val ) and then just implode that returned array

so in your case:

echo implode(',', array_column(mysqli_fetch_array($query), 'email'));

Answer 3

Its not working because you are storing your data into multidimensional array here:

$datos_seleccionados[] = array(
        'emails' => $row['email']
    );

Using echo implode(",", $datos_seleccionados[$i]); inside a for look also an issue, it means, you are imploding an array with comma, you can just do it as @Rakesh suggested:

Solution (i am using this code with some optimization) :

if($count > 0){ // if count exist
    $datos_seleccionados = array(); // initiate
    while($row = mysqli_fetch_array($query)){
        $datos_seleccionados[] = $row['email'];
    }
    echo implode(",",$datos_seleccionados);
}
else{
    echo "No result found";
}