[pyar] OT: Comparación de queries

[Sebastian Bassi]

2010/6/20 Sebastian Bassi <sbassi en clubdelarazon.org>:
> Porque lo que hice entiendo que es un inner join.

Aca copio lo que dice Wikipedia al respecto (que es lo mismo):

SQL specifies two different syntactical ways to express joins:
"explicit join notation" and "implicit join notation".
The "explicit join notation" uses the JOIN keyword to specify the
table to join, and the ON keyword to specify the predicates for the
join, as in the following example:
SELECT *
FROM   employee
       INNER JOIN department
          ON employee.DepartmentID = department.DepartmentID
The "implicit join notation" simply lists the tables for joining (in
the FROM clause of the SELECT statement), using commas to separate
them. Thus, it specifies a cross-join, and the WHERE clause may apply
additional filter-predicates (which function comparably to the
join-predicates in the explicit notation).
The following example shows a query which is equivalent to the one
from the previous example, but this time written using the implicit
join notation:
SELECT *
FROM   employee, department
WHERE  employee.DepartmentID = department.DepartmentID