Dynamic Sql Query

I am using a SQL query tag in my UDT and I am trying to use two parameters, Line_Name and Machine, in the Select statement. Using the parameters does not yield a value but using the actual tag or value does. The query below shows what I am trying to do. Is my syntax correct? Am I trying to do something that cannot be done this way?

Select 500 - Sum(Actual*{[~]{Line_Name}/{Machine_Name}/Remaining_Wire})
From EOSData
Where EOSDate > '{[Weld]{Line_Name}/{Machine_Name}/Latest_Drum_Change_Out_Date}'

You cannot nest brace substitutions. You’ll have to make an expression that assembles the nested part, then put that in your SQL.

Can you post a link for this?