Error Message when Right Join is not zero

[gabbyparks97]

I am trying to add a control check into my workflow that sends either a warning message or errors out when the right join is not zero. Essentially I need a control that ensures that the data from the right side of my join is matching the data from the left side and nothing is falling out. 

Any recommendations on best way to approach? Thanks 

[alexnajm]

Look at the Message tool!

[alexnajm]

You could also look at the Test tool