Question d’entretien chez Cognizant

1) What is a correlated sub query? Write an example query? 2) What is decode? Write an example query? 3) What is plsql records? Write a simple record procedure? 4) What is trigger? Write an example trigger? 5) What is exception handling? Define a exception and handle the exception at exception block? 6) What is index? Types of index? 7) Difference between row num and row id? 8) Write query to get top 5 highest salaries from employee table using row num? 9) What is oracle partitioning ? 10) What is with clause?