How do i get the two letters of a post code using expression?

[#1]

Hello All,

I know am a pain but please bear with me.

what i am trying to achieve is to get the first two letters of a post code in a city and then i want to create an analysis of post codes where accident is more frequent.

below is the address table; what i want is get the first two letters in the postcode then i can use Towncity as a dimension and can drill through the post code, i dont know if am making sense.. any idea will be appreciated

Address:

LOAD AddressID,

    // FKCountryID,

   //  Address1,

   //  Address2,

     TownCity,

     County,

     Postcode

   //  Latitude,

   //  Longitude,

   //  FullAddress,

   //  Deleted,

   //  LastUpdatedDate,

   //  CreatedDate

FROM

Tier1_QVDs\Address.qvd

(qvd);

[kelly_oakley]

Hi, what would this expression be to produce the first half of the postcode?