I need a script, submit to database and redirect

I'm looking for somebody to write a script for me, preferably in php but open to other ideas.

Basic concept, somebody lands on our homepage and checks availability in their area. Postcode input (max 9 chars) and Submit button. (already done)

Postcode - name/id 'zip'
submit name 'did_submit'

I want the basic script to operate like this:

Postcode input form (max 9 chars) - submit
-Convert to uppercase and remove spaces
-Store within database

If
First 4 chars =“AA11,AA12,AA13” then redirect to ‘URL’
Else if
First 3 chars =“B10,B11,B13” Then redirect to ‘URL’
Else if
First 2 Chars =“B1,C1,D2,E3” Then redirect to ‘URL’
Else If
input =“LOCATION, LOCATIOM,NIOACOL” Then reforest to ‘URL’
Else
Redirect to ‘URL’

I think this is the best way to do it, post-codes may fall into 2 IF statements:
Eg, Postcode A31 will fit into A31 and A3,
In this scenario they would both go to the same page anyway, but I don't want to end up in a loop etc, it should make the first valid redirection.

I'm happy to update the code to a full list of post-codes, I will provide a demo list of inputs and the original form for the selected coder.

I would also like to add, the is no validation on the input, but I would like some advice on how to protect it for attacks (injection etc)

Ideally I would like this done this week, Only requirements for the coder are they must be able to communicate clearly in English.