Validation rule first three letters + 8 number

[AccessWillKill]

i need a validation rule i have a field that needs to get the first three letters from another fields value + 8 numbers

for example

Product = Funtime Frank
ShortCode = Fun12345678

the colours are just there to demonstrate what i mean

this is my validation rule
like Select Left (product,3) From tblblues And "########"


its wrong however i don't know where to go from here

 

[Galaxiom]

Your shortcode should not be stored in its full form but displayed on forms and reports as derived value made as a composite of a stored numeric code and the three characters from the product field.

This will not require validation of the three alpha characters as they will automatically reflect those characters from the product field.