Create a string from a fetch(PDO::FETCH_ASSOC) - php

Question

I am trying to build a string made of the results from sql and I do not know how achieve this when the data from the db is bigger than 1.
I was able to do it when the result from the database is one.
$result = $stmt_grade->fetch(PDO::FETCH_ASSOC);
$str ="[{$result['score_access']}, {$result['score_training']},
{$result['score_expectation']}, {$result['score_total']} ]";
but when I needed to loop the fetch_assoc I was not able to assign a value to variables or directly build the string.
while ($resultcount = $stmt_count->fetch(PDO::FETCH_ASSOC)){
$resultcount['subarea'];
}
I have looked everywhere and did not find any solutions or any similar approach to find inspiration. I hope someone can help me. Thank you in advance!

Answer 1

The most obvious way to do this is loop through all of the responses in a while loop, and continually append to your string using the .= operator. You can tell when you run out of records because $result will be false.
I separated each record with a newline. It also looked like you wanted to count results, so I added that, too.
$str = ""; // start with an empty string
$count = 0;
while ( ($result = $stmt_grade->fetch(PDO::FETCH_ASSOC)) !== false ) {
// increment the record count
$count++;
// add a new line to the output string
$str .= "[{$result['score_access']}, {$result['score_training']},{$result['score_expectation']}, {$result['score_total']} ]\n";
}
That should do it.

Answer 2

All you need is to name your string properly.
And then use a proper way to create a JSON string. Which consists of two parts:
Create a array of desired structure. Or at least provide a that structure here to let us to provide you with the code.
Use json_encode().
Assuming you need a nested array like this
[[1,2,3],[1,2,3],[1,2,3]]
the code would be
$result = $stmt_grade->fetchAll(PDO::FETCH_NUM);
echo json_encode($result);

Answer 3

thanks for all the answers provided without you I could not made it. Finally, I achieved the desirable result as follow, probably it is not elegant but works:
$stmt_count= $user->countbyespeciality();
while ($resultcount = $stmt_count->fetch(PDO::FETCH_ASSOC)){
$prueba.= "{$resultcount['subarea']},";
$prueba2.= "{$resultcount['number']},";
}
$string=rtrim($prueba, ",");
$string2=rtrim($prueba2, ",");
$final="[{$string}]";
$final2="[{$string2}]";
The output is [something,something] [1,2,] as expected.
thanks again!