consultilla...

[gnzsoloyo]

Afinemos un poco entonces:

Código MySQL:

mysql> INSERT INTO tabla2
    -> VALUES(2, 154, 2008);
Query OK, 1 row affected (0.00 sec)
 
mysql> SELECT empresa, IFNULL(SUM(facturacion), 0) Facturacion
    -> FROM tabla1 T1 LEFT JOIN (SELECT * FROM tabla2 WHERE ejercicio = 2009) T2 ON T1.id = T2.id
    -> GROUP BY T1.id;
+------------+-------------+
| empresa    | Facturacion |
+------------+-------------+
| Telefonica |         225 |
| Carrefour  |           0 |
| Prisa      |          75 |
+------------+-------------+
3 rows in set (0.00 sec)