Question { Accenture, 30468 }

How would you delete duplicate observations?

Answer

There are two ways of deleting the records from the dataset
with the help of PROC SORT.
1. Using NODUP/NODUPRECS
2. Using NODUPKEY

The first option deletes the records only if all the
variables values are repeated in the subsequent records.

The second options deletes the records only if the value of
the BY variables given in the BY clause are repeated in the
subsequent records.

Question { SAS, 11800 }

What are the joins,types of joins and thier functions?

Answer

There are basically three types of joins,
1. Inner Join
2. Left Join
3. Right Join

Inner Join gives the records which are present in both the
datasets.

Left join gives all the records that are present in left
dataset irrespective of whether they have a matching record
in the right dataset.

Right join gives all the records in the right dataset
irrespective of whether they have a matching record in the
left dataset.