Top 20 PostgreSQL Interview Questions with Answers

Hello guys, if you are preparing for Postgres Interview or a Java development role where PostgreSQL skills are needed but not sure how to prepare, what to prepare etc and looking for PostgreSQL Interview questions with answers then you have come to the right place. Earlier, I have shared 50 SQL Phone interview questions and 6 SQL Query questions and in this article, I am going to share frequently asked PostgreSQL questions with answers. You can use these questions and answers to prepare well for your Job interview and you can also learn essential PostgreSQL concepts by going through these questions.

How to check for Null in SQL Query? IS NULL Example Tutorial

One of the most common SQL Interview questions on Programming interviews is to select some rows from a table that also contains null values. Since many SQL developers are used to using = and != operator on WHERE clause, they often tend to forget the fact that column allows NULL or not. Using = or != is perfectly fine if your column has NOT NULL constraint and you know for sure that there are no NULL values in that column, but it does contain NULLs then your SQL query will return the incorrect result at times. This is one of the most common mistakes but at the same time hard to find SQL bugs if it managed to get into the real environment. In this article, you will learn the right way to check NULL values in SQL queries using IS NULL and IS NOT NULL predicates.

How to drop a column from an existing table in SQL Server? Example Tutorial

Hello guys, In the last article, I have shown you how to add a new column to an existing table in Microsoft SQL Server and today, I'll teach you how to remove or drop a column from an existing table in SQL server. Dropping a column is a trivial task from a new table e.g. you can just use ALTER TABLE table_name DROP COLUMN column_name to drop a column but when it comes to removing a column from existing table, you need to be more careful because it may contain data or it may be referenced from other tables. If a column is associated with another table using foreign key constraint then you cannot remove it until you remove the foreign key constraints.

Why use Date as YYYYMMDD in SQL Server?

When you enter a Date in SQL SERVER for inserting data or filtering data in WHERE clause, what you enter is String. SQL Server infernally converts that formatted String to different date and time data types in Java e.g. DATETIME, DATE, TIME, DATETIME2 and SMALLDATETIME. This conversion is subject to language setting in SQL SERVER, for example, the same date 03/07/2015 can be interpreted as 3rd March 2015 if language setting is US English (MMDDYYYY) and 3rd July 2015 if language is set to British English(DDMMYYYY). To avoid this, you can enter date as YYYYMMDD format, which is considered language neutral and always interpreted correctly by Microsoft SQL Server.

10 Reasons to Learn SQL for Programmers and Software Developers in 2024

Hello guys, if you are on the fence whether to learn SQL or not, or want to learn SQL but not sure whether learning SQL is worth your time and effort then you have come to the right place. Earlier, I have shared best SQL books and courses to learn SQL for Beginners and in this article, I am going to share 10 Reasons to learn SQL. From my 18 years of experience as Software developer and 12 years as a blogger I can safely say that you should learn SQL. In all of these times, I have constantly worked with SQL in my projects and job. While database changes form Oracle to MySQL, to SQL Server, and now PostgreSQL but the knowledge of SQL still pays off. 

5 Examples of GROUP BY Clause in SQL with Aggregate Functions

There is no doubt that SQL is an essential skill and every programmer, developer, DevOps, and Business analyst should know SQL. If you want to learn SQL from scratch then you have come to the right place. Earlier, I have shared many SQL interview questions and the best SQL courses for beginners, and today, I am going to share some GROPU By examples in SQL to write aggregation queries. THE GROUP BY clause in SQL is another important command to master for any programmer. We often use the GROUP BY command along with a select clause for reporting purposes, since the GROUP BY clause is mainly used to group related data together it's one of the most important SQL commands for reporting purposes. 

Top 10 Greenfield Technology you can learn in 2024 (include blockchain, web3, solidity etc)

Technological advancements have ruled the world for centuries, with new innovative concepts taking the limelight in different eras. For example, telephones ruled for quite some time in the field of communication. Then came the internet, and subsequently, many applications developed over the internet. What is the relevance of Greenfield Technology in the course of the evolution of technology? The term “Greenfield” represents a concept used for developing systems in completely new environments alongside calling for development from scratch.

Coursera Meta React Native Specialization Review

 The industry of mobile apps has revolutionized the world and it is needed in almost every company developers can make a mobile app to reach more customers since more consumers are relying on their smartphones every day.It is the best time nowadays to learn mobile app development and choosing a course to start can be a hard job to do so I’ve chosen a course offered on the Coursera platform called Meta React Native Specialization to help you learn mobile app development.

10 Reasons To Learn Kotlin Programming Language in 2024

In the ever-evolving world of technology and programming, it's important to stay ahead of the game and continuously improve your skills. For Java developers, one language that has been making waves in recent years is Kotlin. This language was first introduced in 2011 and has since become a popular choice for developers all over the world. In this article, we'll dive into 10 reasons why you should consider learning Kotlin in 2024. Whether you're a seasoned Java developer or just starting out, Kotlin offers a range of benefits that make it a valuable addition to your skill set. So, let's get started and discover why Kotlin is worth your time and attention!

Top 25 Big Data and Hadoop Interview Questions and Answers

Hello guys, as a Java developer you not just prepare for Java questions but also for different areas related to Java like Big Data and Hadoop depending upon job requirements. If you are going for a Job where Kafka, Apache Hadoop, or Spark is listed as required skill then it make sense to prepare for Big Data Interview questions covering Kafka, Spark and Hadoop. Big Data is e of the most rapidly growing technology is big data. With the rise of Big Data comes a widespread adoption of Hadoop to address important Big Data issues. Hadoop is one of the most widely used frameworks for storing, processing, and analyzing Big Data. As a result, there is always a need for professionals in this industry. However, how do you get a job in the Hadoop field?

Top 15 Cyber Security and Information Security Interview Questions and Answers

Hello guys, If you are preparing for Cyber Security Engineer interviews or just want to learn more about Cyber Security you have come to the right place. Earlier, I have shared best Cyber Security courses and free Cyber Security tutorials and in this article, I am goin to share frequently asked Cyber Security interview questions with answers so that you can revise essential Cyber Security concepts quickly before your interviews. There is no doubt that cybersecurity jobs are the only IT domain that has never experienced a recession yet because companies have a lot of sensitive data in their servers and database so anyone can take advantage of the security weaknesses and exploit them. That's why there is also high demand for Cyber Security experts, but clearing a Cyber Security Job interview is not easy.

Top 20 Blockchain Developer Interview Questions with Answers

Hello guys, if you are preparing for Blockchain developer interviews or looking for any job in the Blockchain technology field but wondering how to prepare then you have come to the right place. Earlier, I have shared best Blockchain courses and Blockchain websites and in this article, I am going to share 20 common Blockchain interview questions with answers. These Blockchain questions not only covers key Blockchain concepts like nodes, hashing, transaction, and different types of Blockchain network like Ethereum, HyperLedger Fabric, Smart Contracts etc but also provide their to the point answers so that you can revise them quickly. If you have worked as Blockchain developer then you can easily answer these questions but if you cannot then you can also check these free Blockchain courses to learn and revise important Blockchain concepts.

How Long Does It Take To Learn Cyber Security?

Hello guys, if you want to become a Cyber Security Engineer or a Cyber Security Analyst and wondering how long it take to learn all essential Cyber Security concepts then you have come to the right place. Earlier, I have shared best Cyber Security online courses, Pen testing certification courses,  and Ethical Hacking online courses to become a Security specialist in 2023 and in this article, I am going to share how you can learn Cyber Security and how much time it take to learn Cyber Security concepts, tools, and practices. Cyber security is a massive industry that involves protecting data from unauthorized access either locally on your devices such as a laptop, computer, phone, router, local network, or the data on the server that holds the companies data such as users information and their credit card. This article will help you estimate the time needed for learning cyber security and which skills are essential.

Top 5 Relational Databases To Learn in 2024

The relational database is like any type of database that is used to store data but in a table format these types of databases are famous among companies and it used to store their client data for later access and analyze their customer behavior for better marketing decisions this article will help you to discover some of the best relational databases used out there. These are also very important skills for any backend developer as they often need to work on Java and also on the backend database used in their project. As a backend or full stack developer, its better to be familiar with relational and NoSQL database to work effectively. 

Groovy - 10 things Java Developers should know

Last year, I got a chance to work with Groovy with one of my client's project. The project which uses groovy a lot for unit testing and configuration build along with some templating engine. In order to understand those big and small Groovy scripts, I started learning Groovy by reading Java Make Groovy. I have to accept that learning a new language is not an easy job, it takes both time and effort to be comfortable with a language even if the language seems relatively easy. Groovy has been designed keeping Java developer in mind and it aims to complement Java by addressing issues which both developers e.g. its verbosity and making things easier for them.