What is the difference between micro urban studies and urban macro study?

There are very distinct differences. 

• Urban planners work with policy that shapes urban development. For example, an urban planner can write policy recommendations for mass transit infrastructure, business development strategies for economic development & job creation, or land use plans for transit-oriented development. 
• Urban designers work with the physical form of cities. For example, an urban designer can any day be working on designing street-scapes and major transportation corridors; parks, open spaces, waterfronts, and plazas; architectural design guidelines for neighborhoods & downtowns.