10+ Telecall Technology Interview Questions and Answers

SQL query to find Nth highest salary, fetch duplicate records, and shell script for Fibonacci series.

• To find Nth highest salary in SQL, use the 'ROW_NUMBER()' function with 'ORDER BY' and 'LIMIT'. Example: SELECT salary FROM (SELECT salary, ROW_NUMBER() OVER (ORDER BY salary DESC) AS rn FROM employees) AS temp WHERE rn = N;

• To fetch duplicate records in SQL, use the 'GROUP BY' and 'HAVING' clauses. Example: SELECT column1, column2, COUNT(*) FROM table_name GROUP BY column1, co...read more

A shell script to check system health

• Check CPU usage using 'top' or 'ps' command

• Check memory usage using 'free' or 'top' command

• Check disk usage using 'df' command

• Check network connectivity using 'ping' command

• Check system load using 'uptime' command

• Check running processes using 'ps' command

Using a for loop to fetch the Fibonacci series.

• Initialize variables for the first two numbers in the series (0 and 1).

• Use a for loop to calculate the next number in the series by adding the previous two numbers.

• Store each number in the series in an array.

• Continue the loop until reaching the desired length of the series.

To delete duplicate records in SQL, you can use the DELETE statement with a subquery.

• Identify the duplicate records using a SELECT statement with GROUP BY and HAVING clause.

• Create a subquery to select the duplicate records.

• Use the DELETE statement with the subquery to delete the duplicate records.

I will investigate the root cause, communicate with stakeholders, and work on resolving the issue as quickly as possible.

• Investigate the logs to identify the root cause of the issue

• Communicate with stakeholders about the downtime and expected resolution time

• Work on resolving the issue by troubleshooting and fixing the underlying problem

• Implement preventive measures to avoid similar downtime in the future

The highest salary in SQL can vary depending on factors such as location, experience, and industry.

• The highest salary in SQL is typically found in roles such as database administrators, data engineers, and data architects.

• Factors that can influence the highest salary include the candidate's level of experience, the location of the job, and the industry.

• For example, a senior database administrator in a major tech hub like Silicon Valley may command a higher salary compared to ...read more

Dense rank function assigns a rank to each row within a partition of a result set, with no gaps in the ranking values.

• Use the DENSE_RANK() function in SQL to assign a unique rank to each row within a partition

• It is similar to the RANK() function but does not leave gaps in the ranking values

• Example: SELECT column1, DENSE_RANK() OVER (PARTITION BY column2 ORDER BY column3) AS dense_rank FROM table_name

Use SQL query with subquery to fetch second highest salary of an employee in Oracle.

• Use ORDER BY and LIMIT to get the second highest salary.

• Use a subquery to exclude the highest salary and then find the maximum from the remaining salaries.

• Example: SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees);

Grep command is used in Unix to search for specific patterns in files.

• Grep stands for Global Regular Expression Print.

• It is a powerful command-line tool for searching text files.

• It uses regular expressions to match patterns.

• Grep can search for patterns in a single file or multiple files.

• It can also search recursively in directories.

• Grep has various options to control the search behavior.

• Some common options include -i (ignore case), -r (recursive search), -l (list files with m...read more

Awk command in Unix is a powerful text processing tool used for extracting and manipulating data.

• Awk command is used for pattern scanning and processing of text files.

• It allows you to specify patterns and actions to be performed on those patterns.

• Awk operates on a line-by-line basis, processing one line at a time.

• It can be used to extract specific columns from a file, perform calculations, and generate reports.

• Awk uses a set of built-in variables and functions for text proces...read more

The HAVING clause is used in SQL to filter groups based on a specified condition.

• HAVING clause is used with the GROUP BY clause to filter groups based on a specified condition

• It is used to filter the results after grouping has been done

• It is similar to the WHERE clause but operates on grouped records

Primary key uniquely identifies a record in a table, while foreign key establishes a link between two tables.

• Primary key is a column in a table that uniquely identifies each record.

• Foreign key is a column in a table that refers to the primary key in another table.

• Primary key cannot have NULL values, while foreign key can have NULL values.

• Primary key ensures data integrity and enforces uniqueness, while foreign key maintains referential integrity.

• Example: In a 'students' table...read more