Question

I’ve got two tables, and I want to compare the data between them, and pick out the data from one table which is not present in the other. I already have a code that works in SQL Server Management, but I need to convert it into Rails or I need to be able to use raw SQL code in my code. Here is the code:

select * from app_servers
where not exists 
( select app, environment, server 
            from stagings
            where stagings.server = app_servers.server_id
            AND
            stagings.environment = app_servers.environment_id 
            AND 
            app_servers.app_id = stagings.app
)

Thanks in advance

Answer 1

Why do you want to convert it? You might use it as it is

AppServer.where(" not exists 
      ( select app, environment, server 
        from stagings
        where stagings.server = app_servers.server_id
        AND
        stagings.environment = app_servers.environment_id 
        AND 
        app_servers.app_id = stagings.app
      )
")