SQL error - discounted price | BI publisher multiplication issue.

I'm in the process of generating the cost price list, but I'm encountering a runtime error.
The error message doesn't provide specific details, so the root cause is unclear.
However, the SQL statements appear to be executing writes correctly,
and both components—the price list and the discount list—function properly on their own.
Could you tell me if there are any improvements that can be made to the SQL structure?

[ADD]

An error seems to occur due to the multiplication in the SQL.
Could you tell me how to perform multiplication in SQL without encountering an error?