How to can i store msg.payload in node red

General
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how to can i store msg.payload in node red

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Hi, if you want a sensible answer, I would suggest you provide additional info. E.g...

  • Where you want to store msg.payload?
  • What is inside msg.payload?
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1)i want to msg.payload to store in a variable and then after wards i will be using that var to Subcriber Topic.
2) msg.payload has user input string.(CR_SUCCESS).

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You can store msg.payload in a var in a function node like this...

var my_var = msg.payload;

I assume you mean subscribe an MQTT topic? You cannot dynamically subscribe to an MQTT topic.

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yes sir i have a gateway code where sub call is there.

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sir.in my code one user case is there where i am publishing twice on a topic (FOB ID and TAG ID).
what is solved:

  1. individual cases of both ID are working i.e if entered id is in my DB then print CR_SUCCESS to the SUB Topic otherwise CR_FAIL.
    what not working:
  2. 3rd case is not working i.e i am taking 2 inputs one is FOB and other is TAG and similarly match both simultaneously with my DB and Print statement to SUB.
    where the problem coming:
  3. as i am entering FOB ,then msg.payload is storing CR_SUCCESS(suppose user entered right ID)but as soon as i am entering TAG again it is showing me CR_SUCCESS(suppose i entered wrong TAG ).why???
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I have remembered you were asking about this same project a couple months ago here: Copying my Door control status back to my Mysql databse

You also have this thread from earlier today: How to calculate 2 msg.id coming from 2 pub different topics simulataneously

If you have two separate messages arriving from MQTT nodes and you need to compare them, you need to get both values into a single message. I pointed you at a recipe for doing that here: How to calculate 2 msg.id coming from 2 pub different topics simulataneously

It is not clear if you have tried anything we have suggested. If there is something you are not sure about, please ask - but please read the material we point you at first.

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Sir thank you answering this,but sir in this task 1 ) and 2) is completed only 3)is remaining.please suggest?

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That is impossible for us to say as you have not shared any specific details of your application.

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Thank you sir,for your help,it means alot for me
Now the output is coming as required.

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