A Simple usage of PIG

1. To Analyze large sets of data we need to use PIG
2. High-level language for expressing data analysis programs (PIG latin)
3. Pig's infrastructure layer consists of a compiler that produces sequences of Map-Reduce programs
4. It can be extended using other languages like java js etc.

pig -x mapreduce
A = load '/user/cloudera/passwd' using PigStorage(':');

B = foreach A generate $0, $4, $5;

dump B; 

The above code prints the columns in etc/passwd file of the local system.

Thanks to the course for the intro.

Other resources to learn about PIG in detail

Here you can learn about PIG 
Mortor PIG cheat sheet

SQOOP

Simple way to remember this

SQltohadOOP : To import SQL data into HDFS


Hive and Impala both can read data from HDFS

Impala Executes by using MapReduce where as Hive runs parallel queries massively.