subquery in FROM must have an alias

I have this query I have written in PostgreSQL that returns an error saying:

> [Err] ERROR:
> LINE 3: FROM (SELECT DISTINCT (identifiant) AS made_only_recharge

This is the whole query:

SELECT COUNT (made_only_recharge) AS made_only_recharge
FROM (
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER = '0130'
    EXCEPT
    SELECT DISTINCT (identifiant) AS made_only_recharge
    FROM cdr_data
    WHERE CALLEDNUMBER != '0130'
)

I have a similar query in Oracle that works fine. The only change is where I have EXCEPT in Oracle I have replaced it with the MINUS key word. I am new to Postgres and don't know what it is asking for. What's the correct way of handling this?

Add an ALIAS onto the subquery,

SELECT 	COUNT(made_only_recharge) AS made_only_recharge
FROM 	
	(
		SELECT DISTINCT (identifiant) AS made_only_recharge
		FROM cdr_data
		WHERE CALLEDNUMBER = '0130'
		EXCEPT
		SELECT DISTINCT (identifiant) AS made_only_recharge
		FROM cdr_data
		WHERE CALLEDNUMBER != '0130'
	) AS derivedTable                           -- <<== HERE

In the case of nested tables, some DBMS require to use an alias like MySQL and Oracle but others do not have such a strict requirement, but still allow to add them to substitute the result of the inner query.