Sql Oracle USING USE?

I am trying to use the "USING" instead of "ON" to make a query.

The problem is that in the "Employees" table it is called "codigo" and in the "trabajan" table it is called "cod_emp".

With the USING how would you join these two tables?
According to the Oracle documentation it is possible, but I can't get it.

SELECT NOMBRE, FUNCION
FROM EMPLEADOS
JOIN TRABAJAN USING (CODIGO,COD_EMP);

The example from the oracle documentation:
https://docs.oracle.com/javadb/10.6.2.1/ref/rrefsqljusing.html

The next query is similar to the one above, but it has the additional join condition that COUNTRIES.COUNTRY_ISO_CODE is equal to CITIES.COUNTRY_ISO_CODE:

SELECT * FROM COUNTRIES JOIN CITIES
    USING (COUNTRY, COUNTRY_ISO_CODE)

Why you shouldn't use "USE" in oracle. A quick rant.

• Can't use it when column names don't match
• Is specific to Oracle and non-portable
• Adds absolutely no value as it is purely syntax sugar.
• Since it is syntax sugar it is hard to compare to other cases where standard syntax is used.

In short, don't use natural joins ever.

From the Oracle 19c documentation, not the JavaDB docs you linked to, and with emphasis added:

> When you are specifying an equijoin of columns that have the same name in both tables, the USING column clause indicates the columns to be used. You can use this clause only if the join columns in both tables have the same name. Within this clause, do not qualify the column name with a table name or table alias.

I you really had to use USING for an assignment then you could do so if you alias one of the column names in a subquery:

SELECT NOMBRE, FUNCION
FROM (
  SELECT CODIGO AS COD_EMP, NOMBRE FROM EMPLEADOS
)
JOIN TRABAJAN USING (COD_EMP);

... which doesn't seem very "comfortable". It's simpler to use ON to handle the name discrepancy:

SELECT NOMBRE, FUNCION
FROM EMPLEADOS
JOIN TRABAJAN ON CODIGO = COD_EMP;

fiddle

It's also a good idea to qualify all of the column names with the table names or aliases so you can see where each column is coming from, and you can use table aliases to make that shorter, e.g.

SELECT E.NOMBRE, T.FUNCION
FROM EMPLEADOS E
JOIN TRABAJAN T ON E.CODIGO = T.COD_EMP;

(But you don't qualify common columns with USING, which personally I find confusing and another reason to avoid that form of join syntax.)

I'd avoid such join definitions.
I'd rather write like below:

SELECT NOMBRE, FUNCION
FROM EMPLEADOS e
JOIN TRABAJAN t on e.CODIGO=t.COD_EMP;

This is more clear and allows for more complex join conditions. Notice also the usage of aliases, which is very important in case you have columns with the same name in two or more different tables in the select statement. I have never used that way of writing the joins or the so-called natural join and never felt I would need to.