Help needed

[#1]

need make a addin that can query data from another addin(premade with ui to extract data and don’t have access to script) that is connected to a database.

Is there a workaround?

Pls help

[#2]

Depends on the add-in. You do have access to the script, but it might be encrypted. You might also be able to control the UI with JSL

[#3]

If it's just grabbing the data from a window, you could always navigate the report it makes using CurrentWindow(), and using XPath to extract out the data, if you could give more information on what the addin is doing we could give some more guidance. 

[#4]

So, AddIn2 should trigger AddIn1 to query data from a database?

don't have access to the script? - What does it mean?
Please open View/AddIns, select AddIn1 und then use the link to open the Installation folder.
Are JSL files in this folder? Please open one and check if it is encrypted.

As @jthi says, a fallback solution is to remote control the GUI of AddIn1 via AddIn2 via JSL.