PTC Interview Questions and Answers

Technical interview questions for Associate Software Engineer position

• To redirect user to a different website without using events, use window.location.replace() method

• To find 7th highest salary from a table in SQL, use subquery or join with itself

• To duplicate tables in SQL, use CREATE TABLE AS or SELECT INTO statement

• Immediately invoked function is a function that is executed as soon as it is defined

• To change array element of array defined by const keyword in JavaScript, use...read more

Prime numbers 1 to 100 and SQL query for 3rd highest salary.

• Prime numbers from 1 to 100: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97

• SQL query for 3rd highest salary: SELECT salary FROM employees ORDER BY salary DESC LIMIT 2, 1

PUT is used to update or replace an existing resource, while POST is used to create a new resource.

• PUT is idempotent, meaning multiple identical requests will have the same effect as a single request.

• POST is not idempotent, meaning multiple identical requests may have different effects.

• PUT requests are typically used for updating existing data, like updating a user's profile information.

• POST requests are typically used for creating new data, like adding a new user to a databa...read more

Singleton is a design pattern that restricts the instantiation of a class to one object.

• Create a private static instance variable of the class.

• Create a private constructor to prevent instantiation from outside the class.

• Provide a public static method to access the instance.

The table tag is an HTML element used to create a table structure on a web page.

• The table tag is used to define the start and end of a table.

• It is typically used in conjunction with the tr (table row) and td (table data/cell) tags.

• Tables can be used to display tabular data, such as a list of items or a grid of information.

• Table tags can also include attributes like border, cellpadding, cellspacing, etc.

• Example:

  Cell 1

  Cell 2

Inner join is an operation that combines rows from two or more tables based on a related column between them.

• Inner join returns only the matching rows between the tables.

• It is performed using the JOIN keyword in SQL.

• The common column used for joining should have the same data type in both tables.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column;