How to access msg payload as variables

[davemc50]

Useful node, well done for creating.

What is the scope or range for "variables" in the bottom box.

Could someone add to the docs to describe how to access msg.topic or msg.payload or other variables that may be in context. Is there a commonly used precursor node this sqlstring node that sets things up? Is there a recommended way to debug this node?

This may be obvious to experienced users, to new users of node-red (like me) it's a complete mystery.

[kevin-holbrook-epicor]

Same issue, the docs need to explain what is supported in the "variables" field.
Flow context values do not seem to be supported.

Looking at the source it appears anything named in the variables list is then derived to msg.{var}.
So don't use "msg.field" just "field". This would also explain why other contexts are not supported, which is disappointing.