How do I retrieve a single row from a table using PHP? - php

Question

I've created a table and stored values in it. The table has a column 'ID' which is unique.
Now I’ve created a form where there is a button marked Retrieve. When I enter the ID and click the Retrieve button, I want to view the data corresponding to this ID.
How do I do this using PHP and MYSQL?
I’ve got some code below, but it isn‘t working. No error message is being showed. But there is no problem with the db connection. Rest of the functions working except for 'RETRIEVE'.
<?php
$dbhost = 'localhost';
$dbuser = 'root';
$dbpass = '';
$dbname = 'DB';
$conn = new mysqli($dbhost, $dbuser, $dbpass, $dbname);
if(mysqli_connect_error())
{
die("couldn't connect" . $conn->connect_error());
}
echo ("connected successfully");
$id = $_POST['Id'];
$name = $_POST['Name'];
$blood = $_POST['BloodGroup'];
if(isset($_POST['insert'])){
$insert = "Insert into ins(Id, name, BloodGroup) values ('$id','$name', '$blood')" ;
if($conn->query($insert) === TRUE) {
echo ("Input data entered successfully");
} else {
echo ("Input data failed to be entered" . $conn->error());
}
$conn->close();
} elseif(isset($_POST['update'])) {
$update = "update ins set Name='".$name."', BloodGroup='".$blood."' where Id='".$id."'";
mysql_query($update);
if($conn->query($update) === TRUE) {
echo ("Data updated successfully");
} else {
echo ("Data cant be updated" . $conn->error());
}
$conn->close();
} elseif(isset($_POST['delete'])) {
$id = $_POST['Id'];
$delete = "delete from ins where Id='".$id."'";
if($conn->query($delete) === TRUE) {
echo ("Data deleted successfully");
} else {
echo ("Data cant be updated" . $conn->error());
}
$conn->close();
}
else {
$id = $_POST['Id'];
$retrieve = "SELECT * FROM ins WHERE Id = ".'$id'."";
$dis = $db->query($retrieve);
$row = $dis->fetch_assoc();
echo 'Details are: '.$row['id'];
}
}
$conn->close();
?>

Answer 1

Change sql select clause into this:
"SELECT * FROM ins WHERE Id = " .$id. " LIMIT 1";

Answer 2

$retrieve = "SELECT * FROM ins WHERE Id = ".$id." LIMIT 1";
The limit will work for you

Answer 3

In the SQL statement ($retrieve), the single quotes are killing it for you. Try either of the following:
Remove the single quotes around $id and keep the rest of the statement the same
Change '$id' to "'{$id}'" (if you're keen on getting the single quotes around the $id value - just in case $id is a text value and not a number)

Answer 4

Try this
$retrieve = "SELECT * FROM ins WHERE Id = ".$id;
$dis = $db->query($retrieve);
$row = $dis->fetch_row();