Re: column check mistake or not? - Mailing list pgsql-bugs

Rodriguez Fernando <rodriguez@ort.edu.uy> writes:
> Yesterday i did a mistake executing one query, i use a column daes not
> exists in the table the result was all rows of the table.
> Platform Fedora 14 32 bits
> Version Postgresql 9.0.2

> The column id_documento not exists in t_log_modificar_deuda, this
> behavior is correct or not?

> query
> select * from t_documento where (importe_deudor_documento >
> importe_documento) or id_documento in (select id_documento from
> t_log_modificar_deuda);

> result all column of t_documento.

Yes, it is.  That's an outer reference to the id_documento from
t_documento, so of course the IN will succeed (assuming id_documento
isn't null and there's at least one row in t_log_modificar_deuda).

Outer references are a SQL feature that bites novices fairly often :-(
but on the other hand sub-selects would be far less useful without them.

            regards, tom lane