How To get the Number of rows scan less when we take difference between the dates

[Amit Tripathi]

mysql> explain SELECT now(),g.gallery_created,g.id as gallery_ids FROM gallery_event g LEFT JOIN tag m on g.id=m.gallery_id WHERE date(now())-date(g.gallery_created) <= 7;
+----+-------------+-------+--------+---------------+---------+---------+---------------------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+---------------+---------+---------+---------------------+--------+-------------+
| 1 | SIMPLE | g | ALL | NULL | NULL | NULL | NULL | 136193 | Using where |
| 1 | SIMPLE | m | eq_ref | PRIMARY | PRIMARY | 8 | prod.g.id | 1 | Using index |
+----+-------------+-------+--------+---------------+---------+---------+---------------------+--------+-------------+
2 rows in set (0.00 sec)



there are 136193 number of rows are there so it scann all the rows while i need data for last 7 days.. ?