SQL query to remove offline machines

Hi,

I'm currently trying to write a query in SQL to remove offline machines. I keep getting the redlines under SEM_AGENT or any other table. Does the below query look right? This is being done in a test environment and I have little to no expierence with SQL or scripting. Thank you for your help!

SELECT UPPER([SEM_AGENT]) as HOST_NAME
     ,case when comp.status=1 then 'ONLINE'
     else 'OFFLINE' end as Status