When checked in MySQL database I see the size as 0 mb. So made some changes and it worked.
1) SSH to your server as root and edit the cpanel.config file
root@server[~]# nano /var/cpanel/cpanel.config
Search for
disk_usage_include_sqldbs=0
and change to
disk_usage_include_sqldbs=1
If the parameter is not present, add it. Save the file and execute the following command:
root@server[~]# /scripts/update_db_cache
Also you can do this from WHM
2) Login to the WHM, goto Tweak Settings >> ‘SQL’ section and enable the following option:
When displaying disk usage in cpanel/WHM include Postgresql and MySQL.
Thats it.