Question d’entretien chez Tata Consultancy Services

These complex PL SQL server questions regularly feature at tech interviews for SQL developers: Define and describe the usage of a linked server. Name and explain the different types of Joins. Explain the different types of authentication modes. Which stored procedure would you run when adding a linked server? Where do you think the user names and passwords will be stored in the SQL server? How would you add email validation using only one query?