Are you sure that you run correct command?
[root@ppu12-0 ~]# plesk db
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 833
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> select count(*) from SBSites;
+----------+
| count(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)