Mutlitple printing values in one field - php

Question

how can i print values from mysql,i have in the table some topics and i need to print them in same row as a comment.
But the code is doing duplicates, also i insert comment into the table.
$sql = "SELECT response.date,response.session, board.id as idboard, Jmeno,Koment,Text, Nazev as 'Nazev', Prezdivka as 'Prezdivka', board.Datum as 'Datel' FROM `board` left join users on board.ID_user=users.ID join response where response.ID_board=board.ID
";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<div class='card'>
<div class='card-header' style='color:red;background-color:lightblue;'>" . $row["Nazev"]. " <a class='float-right'>Uživatel: " . $row["Prezdivka"]. " Datum: " . $row["Datel"]. "</a></div>
<div class='card-body' style='background-color:lightgrey;'>" . $row["Text"]. "</div>
</div>
<a href='prikazy/detail.php?id='>Odpovědi<a><br> " . $row["Koment"]. " <a style='color:pink;'>" . $row["session"]. " " . $row["date"]. " </a>
<form method='post' action='index.php'> <input type='hidden' name='idboard' value=" . $row["idboard"]. " > <input type='text' class='form-control float-right' placeholder='Zadejte nový komentář...' name='komentar'> <br>
<BR><button type='submit' class='btn btn-info float-right' name='komentovat'>Komentovat</button>
</form><br><hr>";
}
} else {
echo "0 výsledků v DB";
}

Answer 1

$sql =
"
SELECT
response.date,
response.session,
board.id as idboard,
Jmeno,Koment,Text,
Nazev as 'Nazev',
Prezdivka as 'Prezdivka',
board.Datum as 'Datel' FROM `board`
left join users on board.ID_user=users.ID
join response where response.ID_board=board.ID
";
The structure of DB which i connect together
Table board (translated for you)
id
name
text
id_category
id_user
date
table response
id
comment
id_board
session_print_name
date
table users
id
name
username
password
date
id_privilegies

Answer 2

I guess the problem is in your query. So the first thing to do is clean it up, make it readable.
SELECT
response.date,
response.session,
board.id as idboard,
Jmeno,
Koment,
Text,
Nazev,
Prezdivka,
board.Datum as Datel
FROM
board
LEFT JOIN users ON board.ID_user = users.ID
JOIN response
WHERE
response.ID_board = board.ID
Now I can immediately spot that your second JOIN is missing its ON part.
That's why you get duplicates.
I don't know the structure of your database, so I cannot add it for you.
Please do not put a query in one long string. Put it in a readable format so you can debug it, like so:
$myQuery = "SELECT
response.date,
response.session,
board.id as idboard,
Jmeno,
Koment,
Text,
Nazev,
Prezdivka,
board.Datum as Datel
FROM
board
LEFT JOIN users ON board.ID_user = users.ID
JOIN response ON response.ID_board = board.ID";