PHP MySQL if equals else INSERT - php

Question

I Have the following code:
<?php
error_reporting(E_ALL);
// connect to your MySQL database here
$dbhandle = mysql_connect('xxx', 'xxxx', 'xxxx');
$selected = mysql_select_db("xxxx",$dbhandle);
// Get the winner data
function setWinner(){
$sql = 'UPDATE user SET winner = 1 WHERE id=(SELECT id FROM user ORDER BY RAND())';
$query = mysql_query($sql) or die (mysql_error());
echo $query;
}
// Get the winner data
function getWinner()
{
$sql = 'SELECT id, fullname, email, number FROM user WHERE winner = 1';
$query = mysql_query($sql) or die (mysql_error());
if(mysql_num_rows($query) == 1) {
$user = mysql_fetch_assoc($query);
} else {
// If there is no winner yet, automatically create one
setWinner();
// Recall the function which should now find a winner
$user = getWinner();
}
return $user;
}
$winner = getWinner();
print_r($winner);
?>
Trying to work with g4vroche's answer but getting this error: You can't specify target table 'user' for update in FROM clause
I used this for a competition to select a random user from the database, but i now need it to look through all the users to see if there's a user that's winner column equals 1 and if there isn't one it should select the random user and update that users winner column with 1.
Any Help greatly appreciated.

Answer 1

I'm using the mysql_query() function just because you used it in your example. You should read up on PDO and implement that instead.
Per my comment above,
require_once "connect_to_mysql.php";
// look for records with `winner` set to 1
$result = mysql_query('SELECT id, fullname, email, number FROM user WHERE winner = 1 LIMIT 1') or die (mysql_error());
if (mysql_num_rows($result) < 1) { // if no records were found, pick a random row
$result = mysql_query('SELECT id, fullname, email, number FROM user ORDER BY RAND() LIMIT 1');
}

Answer 2

I don't know what your winner column actually stores, but assuming it's a boolean, which may contains only 0 or 1, you could do this in a single query :
SELECT id, fullname, email, number FROM user ORDER BY winner DESC, RAND() LIMIT 1;
Which will :
Sort all records on winner column, making rows hanving winner = 1 firsts
Sort equals records with RAND()
So you will get and random result, priority being given to records having winner column equals to "1".
EDIT
I missunderstood your need.
You have two different process here
Get the winner
Set the winner
You should probably split that into two function / methods
// Get the winner data
function getWinner()
{
$sql = 'SELECT id, fullname, email, number FROM user winner=1';
$query = mysql_query($sql);
mysql_num_rows($result) == 1) {
$user = mysql_fetc_assoc($query);
return $user;
}
return false;
}
function setWinner()
{
$sql = 'UPDATE user SET winner=1 ORDER BY RAND() LIMIT 1';
mysql_query($sql);
}
// Call this one time
setWiner();
// Call this any time you want to get the winner's data
$winner = getWinner();
A more lazy approach, will be to make the getWinner() function to call setwinner if there is no winner yet :
// Get the winner data
function getWinner()
{
$sql = 'SELECT id, fullname, email, number FROM user winner=1';
$query = mysql_query($sql);
mysql_num_rows($result) == 1) {
$user = mysql_fetc_assoc($query);
} else {
// If there is no winner yet, automatically create one
setWinner();
// Recall the function which should now find a winner
$user = getWinner();
}
return $user;
}
That's up to your context, but on general point of view it's bad practice, because a function which looks like reading data (getSomething) will, under some circumstances, also alter data (call to setWinner().