Change column data based on data from another column in QTableView?

[adutzu89]

Thank you for your guiding. I finally solved with the following:

QVariant ModelLProd::data(const QModelIndex &index, int role) const
{
    QVariant value = QSqlQueryModel::data(index, role);
    if (value.isValid() && role == Qt::DisplayRole && index.column() == 9) {
        int rand=index.row();
        int val=index.sibling(rand,8).data().toInt();
        if(val==99){
            return value.toString().replace(value.toString(),"0.00");
        }
    }
    return value;
}

QVariant ModelLProd::data(const QModelIndex &index, int role) const
{
    QVariant value = QSqlQueryModel::data(index, role);
    if (value.isValid() && role == Qt::DisplayRole && index.column() == 9) {
        int rand=index.row();
        int val=index.sibling(rand,8).data().toInt();
        if(val==99){
            return value.toString().replace(value.toString(),"0.00");
        }
    }
    return value;
}

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I was looking at the issue the wrong way.