FirstRound : sql is quit difficult because it was based on deep skills in sql .and aptitude is easy.
I did not clear the first round but i advice you to prepare sql syntax as well as lot of practical oriented questions.
if you prepare basics of aptitude is enough as the expect sql skills only.
Interview questions [1]
Question 1
aptitudeQuestions Topic: probability, Boats and Streams SI,CI etc
sql is skill based as well as practical oriented