Not sure how many of you had or have faced nightmares because of handling of NULL in different databases or
tools. NULL is very common nightmare ( NULLs are valid though) because generally people dont anticipate them
and single NULL can cause tremendous pain while summing or doing validations. I have used Oracle, Teradata,
Sybase, Hana, MySQL, Mongo, Abinitio and Informatica, JCL, COBOL in past and faced many issues because of it 
