1) Describe how you would implement a MapReduce job consisting of Map and Reduce description. You can describe it in your own words or as pseudo-code. Keep in mind that map task reads the input file and produces (key, value) pairs. Reduce task takes a list of (key, value) pairs for each key and combines all values for each key. Remember that Map operates on individual blocks and Reduce on individual keys with a set of values. Thus, for Mapper you need to state what your code does given a block of data and for Reduce you need to state what your reducer does for each key. You dont have to explain how to parse the file and extract numbers/names.

1. Same tables:

SELECT Age, COUNT(DISTINCT a.Last)

FROM Employee, Agent

WHERE EID = AID

GROUP BY Age;