Tata Chemicals Interview Questions and Answers

Code to remove duplicates from a list of strings

• Create a new empty list to store unique elements

• Iterate through the given list and add elements to the new list only if they are not already present

• Return the new list without duplicates

Temporary table in SQL is a table that exists temporarily and is automatically deleted when the session ends.

• Temporary tables are created using CREATE TEMPORARY TABLE statement.

• They are useful for storing intermediate results during complex queries.

• Temporary tables are only visible to the current session and are automatically dropped when the session ends.

CTE stands for Common Table Expression, a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement. Views are virtual tables created by a query.

• CTE is defined using the WITH keyword and can be recursive.

• CTEs are mainly used to simplify complex queries, improve readability, and reduce redundancy.

• Views are saved queries that act as virtual tables, allowing users to query the view as if it were a table.

• Views can be used to hide complexity,...read more

DDL stands for Data Definition Language, DML stands for Data Manipulation Language, and DCL stands for Data Control Language.

• DDL is used to define the structure of database objects such as tables, indexes, and views.

• DML is used to manipulate data within the database, such as inserting, updating, and deleting records.

• DCL is used to control access to data within the database, such as granting or revoking permissions.

Window functions in SQL are used to perform calculations across a set of table rows related to the current row.

• Window functions are used to calculate values based on a set of rows related to the current row.

• They allow you to perform calculations without grouping the rows into a single output row.

• Common window functions include ROW_NUMBER(), RANK(), DENSE_RANK(), and NTILE().

Window functions are used to perform calculations across a set of rows in a table.

• Window functions operate on a subset of rows called a window or frame.

• They can be used to calculate running totals, rankings, and moving averages.

• Examples of window functions include ROW_NUMBER, RANK, and LAG.

• SQL joins are used to combine rows from two or more tables based on a related column between them.

• Common types of joins include INNER JOIN, LEFT JOIN, and RIGHT JOIN.

• CTE (Common Table Expre...read more

Lists are ordered collections of items in Python.

• Lists are mutable, meaning their elements can be changed.

• Elements in a list are accessed using indexing.

• Lists can contain elements of different data types.

• Lists are denoted by square brackets [].