Media.net Software Services (India) Database Developer Interview Questions and Answers

To find the second highest salary in a database table, you can use a SQL query with the ORDER BY and LIMIT clauses.

• Use a SQL query with ORDER BY clause to sort the salaries in descending order.

• Use LIMIT 1,1 to retrieve the second highest salary.

• Example: SELECT salary FROM employees ORDER BY salary DESC LIMIT 1,1;

Left join includes all records from the left table and matching records from the right table. Right join includes all records from the right table and matching records from the left table.

• Left join: Returns all records from the left table and the matched records from the right table.

• Right join: Returns all records from the right table and the matched records from the left table.

• Example: Left join - SELECT * FROM table1...read more

Normalization is a process used to organize a database into tables and columns to reduce redundancy and improve data integrity.

• First Normal Form (1NF) - Eliminates duplicate data by ensuring each column contains atomic values.

• Second Normal Form (2NF) - Requires that each non-key attribute is fully functionally dependent on the primary key.

• Third Normal Form (3NF) - Ensures that non-key attributes are not transitively de...read more

Indexes in databases are data structures that improve the speed of data retrieval operations.

• Indexes are data structures that store a small portion of the table data in an optimized format for quick retrieval.

• They help in speeding up data retrieval operations such as SELECT queries by reducing the number of rows that need to be scanned.

• Indexes can be created on one or more columns of a table to improve the performance ...read more