Sure!
# fwconsole mysql
Connecting to the Database…Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4164
Server version: 5.1.73 Source distribution
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Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.
mysql> delete from asteriskcdrdb.cdr where calldate < now() - interval 3 MONTH;
Query OK, 0 rows affected (0.00 sec)
mysql> exit;
Bye
delete from asteriskcdrdb.cdr where calldate < now() - interval 3 MONTH;
You may set delete from asteriskcdrdb.cdr where calldate < now() - interval 6 MONTH;
You will keep the 6 last months.
Please. Do forget to save your database before to launch this kind of request 