How can I do an insert where not exists?

Question

I\'d like to combine an insert query with a \"where not exists\" so as not to violate PK constraints. However, syntax such as the following gives me an Incorrect synta

Answer 1

INSERT INTO myTable(columns...)
Select values...
WHERE NOT EXISTS
   (SELECT *
    FROM myTable
    WHERE pk_part1 = value1,
        AND pk_part2 = value2)

Edit: After reading martins link, If admit, that the best solution is:

BEGIN TRY
    INSERT INTO myTable(columns...)
    values( values...)
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() <> 2627
      RAISERROR etc
END CATCH;