join question

[#1]

This may be a very basic question, apologies.

I have two sets of data that I want to join, but there is a complication.

Here is an example

Table 1 (Trades)

Trade date | Trade ID

1/15/2015, 123456

Table 2 (Ratings)

Effective date | Trade ID | Rating

1/1/2015, 123456, AAA

1/30/2015, 123456, BBB

I need to display the rating for each trade, but the ratings table does not have an entry for every day. I need to display the rating that was relevant on the trade date. So, where the effective date is <= trade date.

Thanks 

[felipe89]

Puedes intentar lo siguiente.

MAXSTRING({<Effective date={">=Trade date "}>}Raiting)

El join lo debe de hacer implicito por el Trade Id.

[felipe89]

Olvidé decirted, esto lo pones en un cuadro de tabla y pones como dimension el Trade ID