Php mysql querys

Hi Guys,

I just want to ask, as I have just started to learn, how the best way to get single items out of a database and equal the single item, ie username, to equal a single variable?

Thanks Alot

 

mysql_query("SELECT * FROM `table` WHERE username = '$username' LIMIT 1");

PHP:

 

Ok, so would that mean:

$username = 'username';
$userlogin = mysql_query("SELECT * FROM `table` WHERE username = '$username' LIMIT 1");

so then $userlogin would equal username correct?

Thanks

 

maybe this helps

function DBsql($sql)
{

$link = mysql_connect("localhost", "xxx", "xxx")
or die("Could not connect : " . mysql_error());
mysql_select_db("database") or die("Could not select database");

$resultx = mysql_query($sql) or die("Query failed : " . mysql_error());

return $resultx;
};


$RS = DBsql("select UserID from UserSessions where username='".$user."';");
$row = mysql_fetch_array($RS, MYSQL_ASSOC);

Echo "UserID = ".$row['UserID'];

 

You wouldn't want to do this for every query.

function DBsql($sql)
{

$link = mysql_connect("localhost", "xxx", "xxx")
or die("Could not connect : " . mysql_error());
mysql_select_db("database") or die("Could not select database");

$resultx = mysql_query($sql) or die("Query failed : " . mysql_error());

return $resultx;
};

PHP:

Do the connect seperately.

This won't work cause $user never gets there.

function LoggedIn(){
$RS = DBsql("select UserID from UserSessions where username='".$user."';");
$row = mysql_fetch_array($RS, MYSQL_ASSOC);

return $row['UserID'];

}

PHP:

 

Ok, say I requested a page like, http://somesite.com/page.php?item=10

therefore the code would be something link this:

$item;
$description = mysql_query("select `id` from `items` where `id`='".$item."';");

therefore if I write:

$text = $description->$item;
echo $text;

then the content of that item will be shown?

Thanks

 

Almost,

<?
/*
 Database connection
*/
$db = mysql_connect("localhost", "root", "WyeValley");
if($db)
{
	if(!@mysql_select_db("help"))
	{
		die("Cannot select database");
	}
}
else
{
	die("Cannot connect to mysql server");
}
/*
 Script start ....
*/
# Set $id from the value of id in the address bar, stripslashes does what it sounds
# like, trim takes away white space from the beginning and end of the variable, just
# incase it exists, and mysql_real_escape_string is some built in sql injection protection
$id = mysql_real_escape_string(stripslashes( trim( $_GET['id'] ) ), $db); 
if($id != "") # If the id is set carry on with operations
{
 	# Query the database to collect the row for the id set from $id, you
 	# want to limit the query, just because it makes good practive to tell
 	# the server exactly what to select, you could go one step further and 
 	# specify the columns you want to retrieve data from,
 	# "SELECT id,title,description FROM `items` WHERE id = '$id' LIMIT 1"
 	# the above line is an example of how to select specific rows from the
 	# table
	$result = mysql_query("SELECT * FROM `items` WHERE id = '$id' LIMIT 1", $db);
	# If the query is successfull and more than one row is affected
	# by the above line, then go ahead and do something with the data
	# in this case, I'll just echo out the whole row
	if($result and mysql_num_rows( $result ) > 0)
	{ 
	  # This is how to achieve a loop over a result
	  # this will collect all the data you need into
	  # an associative array
	  while($temp = mysql_fetch_assoc( $result ))
	  {
	    echo "<pre>";
	    print_r($temp);
	    echo "</pre>";
	  }
	}
	# The query did not succeed, so die
	else
	{
		die("Cannot query databse for $id");
	}
}
else
{
 	# The id is not set, so die
	echo "No ID selected, please include the id in the url like <a href=\"?id=1\">THIS</a>";
}
?>

PHP:

Theres some examples of interaction with some helpful info near by ..... something to remember would be that mysql_query doesnt return text it returns a resource, look further into mysql_result and mysql_fetch_assoc or mysql_fetch_array to get more details on how to retrieve the actual data stored in the database, $res = mysql_query(""); returns 1 or true on success and 0 or false on failure

 

I think this is what your looking for:

$item=9;
$description = mysql_fetch_assoc( mysql_query("select `id` from `items` where `id`='".$item."'") );
echo $description['id'];

PHP:

 

Thanks for the help. I think i'm sorted, else I'll purchase a book down the city today