Get data from mysql database inside for loop with php pdo - php

Question

I have this php code - for loop and on every step , every increment search for data in mysql table aktivnosti
PHP:
for ($i=1; $i<=30; $i++;){
$temp = array();
$temp['ID'] = $i;
// ATTEMP TO GET DATA FROM aktivnosti WHERE id_activity = $i
$rs1 = $db->prepare('SELECT naziv FROM aktivnosti WHERE id_activity=:idd');
$rs1->bindParam(':idd', $i);
$rs1->execute();
$naz = $rs1->fetchColumn();
$temp['activity'] = '<button>'.$naz.'</button>';
$output['data'][] = $temp;
}
$jsonTable = json_encode($output);
So as you can see from code above I try to get data on every $i increment and search if id_activity on table aktivnosti = $i
I get just one result so I get just first 'naziv', I need to get all naziv data from table aktivnosti where id_activity = $i and create:
<button>$naz[0]<button>
<button>$naz[1]<button>
<button>$naz[2]<button>
<button>$naz[how many times id_activity = $i]<button>
How I can do that? Some ideas?
sorry for my engish. Thanks

Answer 1

As pointed out in comments above, you are taking a bad approach here. You should be able to get all this data in a single query. You probably also need to take a look at your schema if you want to have the concept of a fixed number of 30 days with each days related to n number of records. I would suggest two tables
day_list
day_id day_name (or any other day-related data fields)
1 ...
2 ...
... ...
30 ...
days_records
record_id day_id other_data
1 1 ...
2 1 ...
3 3 ...
4 5 ...
...
You would then query this like:
SELECT
d.day_id AS day_id
dr.record_id AS record_id
dr.other_date AS other_data
FROM day_list AS d
LEFT JOIN day_records AS dr
ON d.day_id = dr.day_id
Sorry for the change in table names, as don't know what your database schema represents in real-world terms.
You then make a single query like:
$query = <<<EOT
SELECT
d.day_id AS day_id
dr.record_id AS record_id
dr.other_date AS other_data
FROM day_list AS d
LEFT JOIN day_records AS dr
ON d.day_id = dr.day_id
EOT;
$rs1 = $db->execute($query);
if (false === $rs1) {
// something went wrong. perhaps log an error
} else {
while($row = $rs1->fetch(PDO::FETCH_ASSOC)) {
$temp = $row;
// check to see if this date has a record
if (empty($temp['record_id'])) {
// this is a day with no associated record.
// do something
}
// not shown - continue to manipulate your $temp as desired
// then add to output array
$output['data'][] = $temp
}
}

Answer 2

If you need both ID and activity:
$sql = <<<EOD
SELECT
id_activity AS ID,
CONCAT('<button>', naziv, '</button>') AS activity
FROM aktivnosti
WHERE id_activity BETWEEN 1 AND 30
ORDER BY id_activity
EOD;
$data = $db->query($sql)->fetchAll(PDO::FETCH_ASSOC);
$jsonTable = json_encode(compact('data'));
If you only use activity:
$sql = <<<EOD
SELECT CONCAT('<button>', naziv, '</button>')
FROM aktivnosti
WHERE id_activity BETWEEN 1 AND 30
ORDER BY id_activity
EOD;
$data = $db->query($sql)->fetchAll(PDO::FETCH_COLUMN, 0);
$jsonTable = json_encode(compact('data'));

Answer 3

try this...
while($naz=$rs1->fetch(PDO::FETCH_OBJ))
{
echo $naz->column1;
echo $naz->column2;
}
instead of
$naz = $rs1->fetchColumn();