Sum of Records per group

I need to add the value field of the table I'm working on, but the sum is done by blocks where the user id is the same.

Exemplifying: This is a shopping cart, each record is a product in the cart with the id of the respective customer. The sum will return the sum of the products in each user's shopping cart.

Iwouldliketodothissum,eitherinSQLdirectly,orinPHP.

Querycode:

publicfunctionbusca(){$query="SELECT CLI.CODCLI, CLI.NOME, CLI.ENDCLI AS ENDERECO, CLI.TELCLI AS TEL, CLI.CELCLI AS CEL, " .
             " PROD.NOMEPROD AS PRODUTO, CAR.QUANTIDADE, CAR.VALOR, CAR.INGREREMOV, " .
             " PAG.NOME AS FORMAPAG, FIN.CODCAR AS NUMPEDIDO, FIN.TROCOPARA AS TROCO " .
             " FROM CARRINHO CAR, CLIENTE CLI, PRODUTO PROD, FINALIZADO FIN, PAGAMENTO PAG " .
             " WHERE CLI.CODCLI = CAR.CODCLI AND " .
             " CAR.CODPROD = PROD.CODPROD AND " .
             " (FIN.CODCAR = CAR.IDCAR AND " .
             " FIN.CODCLI = CAR.CODCLI) AND " .
             " PAG.CODIGO = FIN.FORMAPAG " .
             " ORDER BY FIN.HORA";
             var_dump($query);
    $db = new PDO("mysql:host=localhost; dbname=mizy_sushi_bar; charset=utf8;", "root", "");
    $item = $db->prepare($query);
    $item->execute();
    $count = $item->rowCount();
    if ($count > 0) {
        $vetor[] = array("resultado" => "ok");
        $result = $item->fetchAll(PDO::FETCH_ASSOC);
        $pos = $registro = 0;
        foreach ($result as $linha) {
            foreach ($linha as $key=>$value){
                //$keys = array_keys($linha);
                //$valor = $linha[$keys[$pos]];
                $chave = key($linha);
                next($linha);
                array_push(strtolower($vetor[$registro][$key]), $valor);
                $vetor[$registro][strtolower($key)] = $value;
                $pos++;
            }
            $registro++;
        }
        return json_encode($vetor, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_FORCE_OBJECT);
    }
}

What is returned:

{
    "0":{
        "resultado":"ok",
        "codcli":"1",
        "nome":"Jhonatan Pereira",
        "endereco":"Endereço completo",
        "tel":"2100000000",
        "cel":"21000000000",
        "produto":"Produto Teste2",
        "quantidade":"3",
        "valor":"90.00",
        "ingreremov":"nenhum",
        "formapag":"DINHEIRO",
        "numpedido":"1",
        "troco":"0.00"
    },
    "1":{
        "codcli":"1",
        "nome":"Jhonatan Pereira",
        "endereco":"Endereço",
        "tel":"2100000000",
        "cel":"21000000000",
        "produto":"Prod Teste",
        "quantidade":"5",
        "valor":"125.00",
        "ingreremov":"nenhum",
        "formapag":"DINHEIRO",
        "numpedido":"1",
        "troco":"0.00"
    }
}

NOTE: In this case, the third row of the table is not in JSON because of other criteria outside the case (unfinished purchase).

What do I want it to return (last line of the two objects):

{
    "0":{
        "resultado":"ok",
        "codcli":"1",
        "nome":"Jhonatan Pereira",
        "endereco":"Endereço completo",
        "tel":"2100000000",
        "cel":"21000000000",
        "produto":"Produto Teste2",
        "quantidade":"3",
        "valor":"90.00",
        "ingreremov":"nenhum",
        "formapag":"DINHEIRO",
        "numpedido":"1",
        "troco":"0.00",
        "soma":"215.00"
    },
    "1":{
        "codcli":"1",
        "nome":"Jhonatan Pereira",
        "endereco":"Endereço",
        "tel":"2100000000",
        "cel":"21000000000",
        "produto":"Prod Teste",
        "quantidade":"5",
        "valor":"125.00",
        "ingreremov":"nenhum",
        "formapag":"DINHEIRO",
        "numpedido":"1",
        "troco":"0.00",
        "soma":"215.00"
    }
}

NOTE: Redundancy of the "sum" key is not a problem at the moment. The third record, whose value is 60.00, would enter as 60.00 even though it has no other records from the same customer.

Link to the .sql file that creates the tables and inserts the data:

link