QSqlQuery, MariaDB, error in Insert but I can't see it.

[SPlatten]

I have written a C++ and this uses the QJSEngine to allow me to write JavaScript and then run the scripts without recompiling the C++.

I've written a series of API routines in C++ that I expose to the JavaScript. I'm currently working on the database API and there is a problem with the demo insert, this is the text:

INSERT INTO `tblTest` (`dtWhen`, `tmWhen`) VALUES (?,?)

The parameters to along with this are:

["2020/7/16", "15:43:52"]

I sent this to the C++ as a JSON object:

     {"op":"insert"
    ,"sql":"INSERT INTO `tblTest` (`dtWhen`, `tmWhen`) VALUES (?,?)"
 ,"fields":["biPri", "dtWhen", "tmWhen"]
 ,"params":[ds, tm]
,"success":"onRowResults"
,"failure":"onFailure"}

This is part of the C++ that processes the JSON and performs the query:

QString strSQL = itrSQL->toString();
QSqlQuery query(strSQL);

if ( itrParams != objDB.end() ) {
    QJsonArray aryParams = itrParams->toArray();

    for( int i=0; i<aryParams.count(); i++ )  {
        QVariant varParam(aryParams.at(i).toVariant());
        query.addBindValue(varParam);
    }
}
QSqlError err = query.lastError();

The error I'm seeing is:

INSERT INTO `tblTest` (`dtWhen`, `tmWhen`) VALUES (?,?)
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '?,?)' at line 1 QMYSQL: Unable to execute query

As far as I can see there is nothing wrong with the syntax and the parameters are valid, this is the table structure:

CREATE TABLE `tblTest` (
  `biPri` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `dtWhen` date DEFAULT NULL,
  `tmWhen` time DEFAULT NULL,
  PRIMARY KEY (`biPri`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

[SPlatten]

Actually, just spotted the error after I posted the correct code is:

    QString strSQL = itrSQL->toString();
    QSqlQuery query;
    query.prepare(strSQL);

    if ( itrParams != objDB.end() ) {
        QJsonArray aryParams = itrParams->toArray();

        for( int i=0; i<aryParams.count(); i++ )  {
            QVariant varParam(aryParams.at(i).toVariant());
            query.addBindValue(varParam);
        }
    }
    query.exec();