Can some tell me what're the differences between melee AI and campaign AI?

I'm still working on my map and would like to know which AI to choose. I suppose melee AI teach the computer to do what it does in a melee map with computer, such as build, recruit, attack, etc. But how about campaign AI? How is it different from melee AI?

Thanks!

its better to command the unit yoursself , like attack when your hero is near , or let them patrol. if you are asking your enemy to build , try campaign
i am new so dont blame me if i am wrong =)

sorry, i think i don't understand your explanation. Or is that you misunderstood my question? I just want to know what are the differences between using campaign AI and melee AI when making a new map.