Updating a mysql database based on case statements - php

Question

I really need help on this one. I'm trying to do a mysql update based uisng case but i don't think i'm getting it right.
Here is what i'm trying to achieve.
I have a table with the following fields
user_id, rank, weekly, monthly, justwinners
1 9 0 0 0
2 29 0 0 0
3 8 0 0 0
4 10 0 0 0
5 12 0 0 0
What i want to achieve is to update the weekly, monthly and justwinners fields based on specific dates
Lets say i have a start date of 5/07/2011.
$startdate = 5-07-2011;
At the end of one week which is 12/07/2011 i want to update the weekly field of the user with highest rank to 1. Also at the same time update justwinners
field of the next 3 users with the highest rank to 1.
At the end of the second week which is now 19/07/2011, i want to update the weekly field of the user with highest rank whose value is still '0' to 2 and also update
the justwinners field whose value is still '0' to 2.
This will continue until i get to one months time when i will update the monthly field.
This is what i have been able to come up with so far which is not working.
//Initiate the database connection here
function get_db_conn() {
$conn = mysql_connect(HOST, DB_USER, DB_PASSWORD) or die('Could not Connect!');
mysql_select_db(DATABASE, $conn) or die ('could not connect to database');
return $conn;
}
function updateWinners( $limit, $field ) {
$conn = get_db_conn();
switch($field) {
case "weekly" :
$limit = 1;
case "monthly" :
$limit = 1 ;
case "giftpack" :
$limit = 10 ;
default:
$limit = 1 ;
}
$sqlquery = "SELECT * FROM application rank DESC " ;
$sqlquery .= " where $field < 1 ";
$sqlquery .= " LIMIT $limit ";
$result = mysql_query($sqlquery);
$user_data = mysql_fetch_row($result);
if(isset($user_data)) {
$user_data = 0 ;
while($user_data){
$uid = $user_data(user_id);
$rank = $user_data(rank);
$query = "INSERT INTO application_winners (user_id, rank, date) VALUES ('$uid', '$rank' 'now()')";
mysql_query($query) or die('Error, insert winners query failed');
switch ($action) {
case "weekly":
$startdate = "5-07-2011";
$sqlquery = "UPDATE application SET weekly = CASE
WHEN (CURDATE() = (startdate * 7))
THEN weekly = '1'
WHEN (CURDATE() = (startdate * 14))
THEN weekly = '2'
WHEN (CURDATE() = (startdate * 30))
THEN weekly = '3'
ELSE weekly
END";
}
$user_data = $user_data + 1;
} //endwhile
}
else {
echo "Error in updating the winners";
}
}
In case you know of any better way to implement this. kindly share.

Answer 1

Just as a remark - you have an insert followed by an update. You could do this in the insert part. Something like:
$query = "INSERT INTO application_winners (user_id, full_name, rank, date, $field) VALUES ('$uid', '$user_fullname', '$rank' 'now()', '$updatevalue')";
mysql_query($query) or die('Error, insert winners query failed');

Answer 2

i did not look at everything closely but you are using the variable "$action" for the second switch but it does not exist anywhere else in your code..

Answer 3

Try changing:
$sqlquery = "UPDATE application SET weekly = CASE
WHEN (CURDATE() = (startdate * 7))
THEN weekly = '1'
WHEN (CURDATE() = (startdate * 14))
THEN weekly = '2'
WHEN (CURDATE() = (startdate * 30))
THEN weekly = '3'
ELSE weekly
END";
to:
$sqlquery = "UPDATE application SET weekly = CASE
WHEN (CURDATE() = (startdate * 7))
THEN '1'
WHEN (CURDATE() = (startdate * 14))
THEN '2'
WHEN (CURDATE() = (startdate * 30))
THEN '3'
ELSE weekly
END";