mysqli->fetch_row

[prathameshkakade]

Hello Everyone,I was learning connecting MySQLi with PHP.I wanted to display the names of all the databases on my server.I used the following code.

<?php
$server = 'localhost';
$user = 'root';
$pass = 'pass';
$mysqli = new mysqli($server,$user,$pass);

if($mysqli->connect_error)
die("Could not connect to server.<br/>");

$query = "SHOW DATABASES";

if($result = $mysqli->query($query))
{
	while($row = $result->fetch_row())
	{
		printf("%s<br/>",$row[0]);
	}
}
?>

I am getting the desired result,but I didi not understand the functions fetch_row() and fetch_assoc properly.

and why are we using the indice '0' in the line

printf("%s<br/>",$row[0]);

I tried using 1,but it gave me errors.I did not understand what was given on php.net manual.

Someone please explain me in detail.

Thank you.

[phpzer]

Hello Everyone,I was learning connecting MySQLi with PHP.I wanted to display the names of all the databases on my server.I used the following code.

<?php
$server = 'localhost';
$user = 'root';
$pass = 'pass';
$mysqli = new mysqli($server,$user,$pass);

if($mysqli->connect_error)
die("Could not connect to server.<br/>");

$query = "SHOW DATABASES";

if($result = $mysqli->query($query))
{
	while($row = $result->fetch_row())
	{
		printf("%s<br/>",$row[0]);
	}
}
?>

I am getting the desired result,but I didi not understand the functions fetch_row() and fetch_assoc properly.

and why are we using the indice '0' in the line

printf("%s<br/>",$row[0]);

I tried using 1,but it gave me errors.I did not understand what was given on php.net manual.

Someone please explain me in detail.

Thank you.

Hello,

the function fetch_row() takes all the collumns in the database and puts them in an idexed array. In PHP arrays start with index 0, your query generates a mysql output like this (output might be different depending on your mysql version):

+--------------------+
| Database           |
+--------------------+
| information_schema |
| database_one       |
| database_two       |
+--------------------+

As you can see the only column in there is "Database", so column number one (index 0) is the only column you can access. If you try to access the value 1 you are asking PHP to do something it can't do so it's why it shows an error.

 

The function fetch_assoc() returns an associative array, an associative array it's something like this: 

array(
    "key" => "value",
    "key2" => "value2",
    "key3" => "value3" // and so on
)

Fetch_assoc is really useful when you don't know on what index the column are but you know the names of them. Hope I explained myself, if you didn't understand just say it, I will explain it differently.