Text box value based on query

[Dmak]

Hi there,

I'm in the process of making a database to handle ad campaigns.

I have a creatives table logging the creatives;
Fields;
Size
Format
Theme
Colour
Wording

I have a campaigns table logging the campaigns;
Fields
CreativeID
Network
Country
Status

The client provides me with a landing url that is dependent on Size and Country.

I have a landing urls table to store the URLS and this links to the same lookup tables holding Country and Size data.

What I want is a text box that queries the form fields; Size and Country and gives me the correct landing URL.

Brain not working today, please help, thank you!