CODEWITHSUNDEEP
phpmysqlarrays
Dingo Bruce
Dingo Bruce

Reputation: 405

Strange associative array behaviour in PHP

I am trying to create an associative array in PHP.

The idea is to store an "item Id" as the array key and the total spend on that item Id as the value.

I am using the following code to get data out of my MYSQL two separate tables, one that contains the item info and one that contains a list of expenses.

    // GET ITEM DATA FROM DB
    $getItemData = mysql_query("SELECT * FROM items;");

    // CREATE ARRAY
    $orderItemsBySpend = array();

    // LOOP THROUGH ITEMS AND CALCULATE SPEND IN LAST 30 DAYS
    while($itemData = mysql_fetch_assoc($getItemData)){ 


        $getItemExpenses = mysql_query("
        SELECT SUM(cost)
        AS productExpenses
        FROM expenses
        WHERE itemId = $itemData[id]
        AND date BETWEEN DATE_SUB(NOW(), INTERVAL 30 DAY) AND NOW();");

        $itemExpenses = mysql_fetch_assoc($getItemExpenses);

        // SET TOTAL SPEND VARIABLE
        $totalProductSpend = $itemExpenses['productExpenses'];

        // SET ITEM ID VARIABLE
        $itemId = $itemData[id];

        // ADD KEY AND VALUE TO ARRAY
        $orderItemsBySpend[$itemId] = $totalProductSpend;

        // PRINT ARRAY FOR TESTING PURPOSES
        print_r($orderItemsBySpend);
    }

Unfortunately instead of getting something like this, as I would expect (and am hoping for!)

Note the 0.00 values are only down to the fact there is only limited data in the expenses table.

Array (
[1] => 14.01
[2] => 0.00
[3] => 0.00
[4] => 0.00
[5] => 0.00
[6] => 20.24
[7] => 0.00
[8] => 0.00
[9] => 0.00
)

Instead I am getting this:

Array ( 
[0] => 14.01
) 

Array ( 
[0] => 14.01
[1] => 0.00
)

Array ( 
[0] => 14.01
[1] => 0.00
[2] => 0.00
)

Array (
[0] => 14.01
[1] => 0.00
[2] => 0.00
[3] => 0.00
) 

etc.

My question is: Why is this strange "incremental pattern" of arrays being created? And why is the array key not being set as the item Id?

The first array should have key of 1 (the first item Id), not 0.

All advice appreciated!

Thanks,

Bruce.

Upvotes: 2

Views: 66

Answers (2)

drew010
drew010

Reputation: 69967

$itemId = $itemData[id]; is the problem.

The variable $itemData[id] doesn't exist in the context of that loop so it results in a null value and then

$orderItemsBySpend[$itemId] = $totalProductSpend;

effectively becomes 

$orderItemsBySpend[] = $totalProductSpend;

Instead try:

$itemId = $itemData['id'];

Upvotes: 0

Death-is-the-real-truth
Death-is-the-real-truth

Reputation: 72299

The problem is you are printing your array at wrong place.It is inside loop right now that's whay it is printing in that manner.Just remove it inside while() loop and put it outside loop. Do like below:-

while(){
}
print_r();

Note :- An useful suggestion is to switch to mysqli_* or PDO is best, because mysql_* is officially deprecated.

Upvotes: 3

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