Finding unmatched records with SQL

Question

I'm trying write a query to find records which don't have a matching record in another table.

For example, I have a two tables whose structures looks something like this:

Table1
    State | Product | Distributor | other fields
    CA    | P1      |  A          | xxxx
    OR    | P1      |  A          | xxxx
    OR    | P1      |  B          | xxxx
    OR    | P1      |  X          | xxxx
    WA    | P1      |  X          | xxxx
    VA    | P2      |  A          | xxxx

Table2
    State | Product | Version | other fields
    CA    | P1      |  1.0    | xxxx
    OR    | P1      |  1.5    | xxxx
    WA    | P1      |  1.0    | xxxx
    VA    | P2      |  1.2    | xxxx

(State/Product/Distributor together form the key for Table1. State/Product is the key for Table2)

I want to find all the State/Product/Version combinations which are Not using distributor X. (So the result in this example is CA-P1-1.0, and VA-P2-1.2.)

Any suggestions on a query to do this?

Answer 1

SELECT
    *
FROM
    Table2 T2
WHERE
    NOT EXISTS (SELECT *
        FROM
           Table1 T1
        WHERE
           T1.State = T2.State AND
           T1.Product = T2.Product AND
           T1.Distributor = 'X')

This should be ANSI compliant.

Answer 2

In T-SQL:

SELECT DISTINCT Table2.State, Table2.Product, Table2.Version
FROM Table2 
  LEFT JOIN Table1 ON Table1.State = Table2.State AND Table1.Product = Table2.Product AND Table1.Distributor = 'X'
WHERE Table1.Distributor IS NULL

No subqueries required.

Edit: As the comments indicate, the DISTINCT is not necessary. Thanks!