Create table using 2 tables and a third with multipliers

Hello!

I hope I can explain what im trying to attemp

I have 3 tables:

Table 1& Table 2 have the following structure

DATE | Name | Value

(date)| ID 1  | Value 1

I have many ID's with a vuale for each date

Both tables have the same ammount of dates but different IDs and values

I want to mix both tables using a third table wich is like this:

ID Table 1 | ID Table 2 | factor

a               |  b              |0.2

a               |  c               |.4

And so on 

I want to create a new table that prints the following column:

Date    |   ID  Table 1 |   Value

Where value = value(ID1 Table 2) * factor(Corresponding to that id) + value(ID2 Table 2) * factor .....

I hope I was clear enough if not i can bring an example

Thanks in advance