i don't know how to do this, but for the uptime you have 2 choices
1. Use "adminer" to connect to the mysql database and do a query
in OCS-inventory 2.1.2 this query works
select time,userid,name from uptime inner join hardware on uptime.HARDWARE_ID = hardware.ID order by time+0
2. you can use glpi - the new glpi import plugin
http://plugins.glpi-project.org/#/plugin/ocsinventoryng
can import the uptime from ocs-inventory and glpi can display the uptime in a column
Also the search capability is far more better in glpi and you can save searches in glpi
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