Re: Hint for a query

On Nov 4, 2011, at 0:37, Efrain Lopez <tecnomaya(at)cabsagt(dot)com> wrote:

> I have this tables
>
>
> Table: Contact
> IdContact
> First Name
> Second Name
> … other columns
>
> Table: Employee
> IdEmployee
> IdContact, related to Contact table
> … other columns
>
> Table: Salesman
> IdSaleman
> IdEmployee, if salesman is employee, related to Employee table
> IdContact, if salesman is not an employee, related to Contact table
>
>
> I need a query
>
> Id Salesman - Second name - First name
>
> But I can't figure how to do it, can someone can give advise?
>
> Thanks
>
>

SELECT + JOIN

The query you seek seems too simple that either you have not learned how to do simple SELECTS with multiple tables OR you are not clear regarding what is confusing you.

The documentation and other books/articles on basic SQL will help in the first case. Showing what work you have tried up to this point will help with the second.

Your tables also will be cumbersome to use as designed, but your immediate question is easily answered with the existing schema. In short the link to contact from salesperson is questionable since employee already links there. There is not enough context to provide alternatives but it is worth looking into.

David J.