how to summarize two fields?

CathMulder

I feel a bit stupid, but i can't get it working.
I have 2 int fields, (purchase, marge) and i want to display this computed value:
purchase*((100+marge)/100)

Trying:

        { data: null,
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchase + row.tbl_article.marge )}},

        { data: null,
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchase * row.tbl_article.marge )}},

        { data: null,
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchaseb*b((b100 + row.tbl_article.marge) / 100) )}}

When purchase would be 40 and marge would be 10:
outcome:
first example = 4010
second example = 400 = what to expect
third example = 4004

it seems the + sign combines the field instead of computing the value, but the multiply works correct.
What am i doing wrong here?

kthorngren

Sounds like your data are strings not numbers. You will need to convert them. This article discusses some options.

Kevin

CathMulder

Thanks for answering but they are both numbers. Thats why i added the multiply.

purchase int(11)
marge int(11)

The multiply is doing the expected job. The plus on the same data isn't.

kthorngren

row.tbl_article.purchase + row.tbl_article.marge

This is a simple Javascript statement. Datatables does not do anything with or affect this statement. In order to understand the problem we will need to see the data. Please post a link to your page or a test case showing the problem.
https://datatables.net/manual/tech-notes/10#How-to-provide-a-test-case

Kevin

halioris

You say they are numbers but you said that you expected the result of 40 + 10 to be 4010. If they are numbers the result would be 50. If they are strings the result would be 4010. However if they are strings then 40*10 is definitely not going to be 400. Hence we need to see your data and example.

CathMulder

Sorry, i can't post a link to my page. This is my script and below are two printscreens.
One of my sql database and one from the browser.
And yes, i know this is a simple statement but i don't understand why the multiply works correct and the sum doesn't.

$(document).ready(function() {
editor = new $.fn.dataTable.Editor( {
ajax: '../../controllers/article.php',
// volgorde in de crud
table: '#example',
fields: [ {
label: 'Artikel:',
name: 'tbl_article.name',
type: 'text'
}, {
label: 'Leverancier:',
name: 'tbl_article.user_id',
type: 'select'
}, {
label: 'Categorie:',![]

            name: 'tbl_article.site_id',
            type: 'select'
        }, {
            label: 'Inkoopprijs:',
            name: 'tbl_article.purchase'
        }, {
            label: 'Marge:',
            name: 'tbl_article.marge'
        }
    ]
} );

$('#example').DataTable( {
    dom: 'Bfrtip',
    ajax: {
        url: '../../controllers/article.php',
        type: 'POST'
    },
    // volgorde in de tabel
    columns: [
        { data: 'tbl_article.name' },
        { data: 'tbl_supplier.last_name' },
        { data: 'tbl_category.name' },
        { data: 'tbl_article.purchase' },
        { data: 'tbl_article.marge' },
        { data: null,   // simple sum only for test
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchase + row.tbl_article.marge )}},

        { data: null,  //simple multiply only for test
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchase * row.tbl_article.marge )}},

        { data: null,
                render: function ( data, type, row ) {
                return ( row.tbl_article.purchase*((100 + row.tbl_article.marge)/100) )}}

    ],
    select: true,
    buttons:  [
        { extend: 'create', editor: editor },
        { extend: 'edit',   editor: editor },
        { extend: 'remove', editor: editor }
    ]
} );

} );

(https://datatables.net/forums/uploads/editor/tv/lwwd70uhj9vv.png "")

(https://datatables.net/forums/uploads/editor/vn/vg1hvsedtnq2.png "")

kthorngren

I'm not a JS expert but its a feature of Javascript called Type Coercion. Here is one explanation. You can . see an example here where two strings containing numbers result in a numeric value:
http://live.datatables.net/tecapiqa/1/edit

Datatables tries to automatically discover the data type of the column, explained in the columns.type docs. It could be Datatables is typing the column as string. Is there a non-numeric value in either of those columns?

Kevin

CathMulder

Oke, thanks for the example. I think you are right by thinking datatables is typing the columns as string. But how can i make datatables typing it as numeric? There is no non-numeric value in either one. To be sure I tried in PHP with the same database and colums and it behaves correctly.

CathMulder

Yes, it' solved now. I added the Number function and now it's works correctly.
// simple sum only for test
data: null,
render: function ( data, type, row ) {
return Number(row.tbl_article.purchase) + Number(row.tbl_article.marge) }},

Thanks kthorngren for letting me think in the right direction!

kthorngren

But how can i make datatables typing it as numeric?

You can try columns.type.

You can build us an example with your data. Grab the JSON response using the browser's Developer Tools. If using chrome use the Response tab. Steps for this can be found in this technote. Or you can use the Debugger to get the data to provide to the developers to look at.

Worst case you can use parseInt().

Kevin