Actually, I decided that using a function was a better model, making it easier to debug, and got the following working. Given the using the ? mark notation was proving programmatic.
var theValues = msg.payload.split(',');
var theFields = msg.topic;
msg.topic = `INSERT INTO Ambient(`+theFields+`) VALUES (`+theValues+`);`;
msg.payload=null;
return msg;
The above of course send to the SQL node to process accordingly. I will test what you suggested as well. Thanks for the reply.