How can I get mysql to print rows from a database table

Question

I am trying to learn php from W3schools which includes a mysql section.So far I have completed every other part of the tutorial on w3school except the part that prints content from a database table. For some very weird reason , nothing displays when I run my code. Please how can I get this working and could my problem come from the fact that I am using MariaDB with Xampp instead of Mysql although they said it was practically the same syntax. Here is the code

<?php
$servername = "localhost";
$username = "uhexos";
$password = "strongpassword";
$database = "fruitdb";

// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

// Create database
$sql = "CREATE DATABASE fruitDB";
if ($conn->query($sql) === TRUE) {
    echo "Database created successfully";
} else {
    echo "Error creating database: " . $conn->error;
}

$conn->close();
// Create connection
$conn = mysqli_connect($servername, $username, $password,$database);

// sql to create table
$complexquery = "CREATE TABLE MyFruits (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, 
FruitType VARCHAR(30) NOT NULL,
FruitTaste VARCHAR(30) NOT NULL,
FruitQuantity INT NOT NULL,
DatePurchased TIMESTAMP
)";

if ($conn->query($complexquery) === TRUE) {
    echo "Table Fruits created successfully<br> ";
} else {
    echo "Error creating table:  " . $conn->error;
}
$entry = "INSERT INTO myfruits (fruittype,fruittaste,fruitquantity) VALUES ('orange','sweet','50'),('lemon','sour','10'),('banana','sweet','15')";

if ($conn->query($entry) === TRUE) {
    echo "New records created successfully";
} else {
    echo "Error: " . $conn->error;
}

  $sql = 'SELECT id, fruitname, fruittaste FROM myfruits';

   $retval = mysql_query( $sql, $conn );

   if(! $retval ) {
      die('Could not get data: ' . mysql_error());
   }

   while($row = mysql_fetch_array($retval, MYSQL_ASSOC)) {
      echo "EMP ID :{$row['id']}  <br> ".
         "EMP NAME : {$row['fruitname']} <br> ".
         "EMP SALARY : {$row['fruittaste']} <br> ".
         "--------------------------------<br>";
   }

   echo "Fetched data successfully\n";

   mysql_close($conn);
?>

this is the output I get from all my echos.

Error creating database: Can't create database 'fruitdb'; database existsError creating table: Table 'myfruits' already existsNew records created successfully

or

Database created successfullyTable Fruits created successfully
New records created successfully

Answer 1

Based on the error message, you managed to create the database and tables once and now each time you run the code it fails because you can't reuse the names.

You definitely don't want to have code trying to erase & start fresh on your database every time. In fact, most often I find that you don't even create the database inside your regular code but use phpMyAdmin or some other admin page to do that. But creating tables inside code is normal enough. Two options:

1 - Create the table only if it does not already exist. This is extremely safe. However, if you want to start a table over again with a new structure, or start with it always empty, that won't work. To do that, just change CREATE TABLE to CREATE TABLE IF NOT EXISTS

2 - Delete the table before creating it. Before each CREATE TABLE command, add a command like DELETE TABLE IF EXISTS MyFruits

Answer 2

Remember database name is Case-insensitive, so it doesn't matter whether you create a DB name "fruitdb" or "fruitDb" both are same.That is the reason you are getting error. Also you don't have to create a new database when you execute any file. If you have already created the database than you only have make the connection with it. Let's debug your code line by line.

Line 8 -

// Create connection
$conn = new mysqli($servername, $username, $password);

Here you are creating the connection with your database because you have already created that database. If you check your phpmyadmin, you'll find a database named "fruitdb"

Line 10 -

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

Here your checking whether the you are able to connect with your database. If not it will throw the error and your script will stop. Right now your code successfully runs till this point.

Line 15 -

// Create database
$sql = "CREATE DATABASE fruitDB";

Here you are again creating a database with same name and your code stops working as you already have it.

Answer 3

The error was from this line $sql = 'SELECT id, fruitname, fruittaste FROM myfruits';

I accidentally put fruitname instead of fruittype and that is what caused it to fail. So for anyone else with thi problem my advice is to check your variable names if you are 100% sure of your syntax. Thanks for all the help.