Top 6 Free SQL Courses for Beginners to Learn Online in 2025 - Best of Lot

Hello guys, we are already in the second week of New year, and everyone is talking about their goals to improve them as a better person, a better programmer, or better health. If you have also made your goal, and one of them is to improve your SQL skill, you have come to the right place because I will share some of the free online courses to learn and master SQL this year. The list includes a free course from Udemy, a popular online portal to learn Oracle, PostgreSQL, and Microsoft SQL Server. Yes, I have tried hard to include free courses on different databases to choose the course you want. 

Top 5 Online Courses to Learn MongoDB NoSQL Database in 2025 - Best of Lot

MongoDB is one of the leading NoSQL databases and it was on my radar for a long time but I never get a chance to learn or work on it, but Recently I got an opportunity to use MongoDB for one of our projects and I learned a lot on the way. In this article, I will introduce MongoDB and how to learn MongoDB so that you can use it in your project. In this article, I will share some of the online courses which I have taken to understand everything up to the basic CRUD (Create, Retrieve, Update, Delete) operations on MongoDB. I have also read a couple of books and followed some tutorials but these courses were my main source to learn Mongo DB.

Top 10 Courses to Learn SQL and Database in 2025 - Best of Lot

Hello guys, if you are a computer science graduate or new to the programming world, interested in learning SQL, and looking for some excellent resources, like books, courses, and tutorials to start with, then you have come to the right place. In the past, I have shared some of the best SQL books and tutorials, and today I am going to share some of the best SQL and database courses to learn and master this useful technology. If you don't know what SQL is and why you should learn it, let me give you a brief overview of SQL for everyone's benefit. SQL is a programming language to work with a database. You can use SQL to create database objects, like tables, stored procedures, etc., and also to store and retrieve data from the database.

Top 7 Courses to learn PostgreSQL Database in 2025 - Best of Lot

PostgreSQL is one of the most popular databases after the big three - Oracle, SQL Server, and MySQL. PostgreSQL is commonly known as Postgres and is often referred to as the world's most advanced open source database. If you are looking to learn PostgreSQL in 2025 and looking for some useful resources like books, tutorials, and courses then you have come to the right place. In this article, I am going to share some of the best PostgreSQL online courses for beginners. These courses will cover topics ranging from installations to writing basic queries and retrieving data from tables. you will also explore the logic of SQL Joins, and a few best practices which are essential while working in a real-world, production PostgreSQL database.

Top 5 Websites to Learn SQL Online for FREE - Best of Lot

SQL is one of the most important skills for any programmer be it a Java, C++, Python, JavaScript, or Ruby developer. Almost 95% of the Java applications use a relational database in their back-end and almost all web applications use the database. In recent years, one of the most common ways to learn any programming skill is online, at your comfort of the office or home and SQL is no different. Learning SQL online has another advantage of a quick head start because you don't need to install a database and create tables to write some SELECT queries. 

Top 5 Books to Learn SQL and Database Design for Programmers and DBAs - Best of Lot

The database design and modeling are one of those topics which rarely get the attention they deserve, especially at the start of the project, but once things have gone out of hand, then everybody talks about them. Comments like - this database is designed poorly, the schema is not performing well, you cannot add a new column easily, etc. becomes very common. The most problem with database design is that it is mainly done by application developers like Java or C++ developer who knows SQL, but they are not the expert on how to design tables and schema. 

How to Find Duplicate values in a Table? SQL GROUP BY and Having Example| Leetcode Solution

Hello guys, if you are wondering how to find duplicate values in a table then don't worry, there are many ways to find duplicate rows or values from a given table. For example, you can use the GROUP BY and HAVING clause in SQL with count function to find all the rows which has same values for a particular column and then filter out rows where count is just one, I mean unique values. This way you can find all the duplicate from a given table. Using group by you can create groups and if your group has more than 1 element it means it's kind of duplicate.

How to use EXISTS and NOT Exists in SQL? Example Query and Tutorial

Hello Guys, you might have heard about how useful the EXISTS clause is helpful in writing sophisticated queries. Still, at the same time, I have also seen that many programmers struggle to understand and use EXISTS and NOT EXISTS clauses while writing SQL queries.  If you are one of them, then you have come to the right place. Today you will learn how to use the EXISTS clause in SQL by picking up a real-world example and an excellent SQL exercise from the LeetCode. Suppose that a website contains two tables, the Customers table, and the Orders table. Can you write an SQL query to find all customers who have never ordered anything?

Top 10 SQL SELECT Query Examples for Beginners

The Select command in SQL is one of the most powerful and heavily used commands. This is I guess the first command anyone learns in SQL even before CREATE which is used to create a table in SQL. SELECT is used in SQL to fetch records from database tables and you can do a lot many things using Select. For example, you can select all records, you can select few records based on the condition specified in the WHERE clause, select all columns using the wild card (*) or only selecting a few columns by explicitly declaring them in a query.

JDBC Batch INSERT and UPDATE example in Java with PreparedStatement

JDBC API in Java allows the program to batch insert and update data into the database, which tends to provide better performance by simple virtue of fact that it reduces a lot of database round-trip which eventually improves overall performance. In fact, it’s one of JDBC best practices to insert and update data in batches. For those who don’t know what is batch insert and update, Java provides several ways to execute SQL queries, one of them is JDBC batch insert and update, on which instead of executing SQL query one by one using either Statement or PreparedSatement, you execute a query in batch and send a batch of the query to the database for execution instead of a single query. 

Difference between LEFT and RIGHT OUTER Joins in SQL - MySQL Join example

There are two kinds of OUTER joins in SQL, LEFT OUTER join and RIGHT OUTER join. The main difference between RIGHT OUTER joins and LEFT OUTER join, as their name suggests, is the inclusion of non-matched rows. Sine INNER join only include matching rows, where the value of the joining column is the same, in the final result set, but OUTER join extends that functionality and also include unmatched rows in the final result. LEFT outer join includes unmatched rows from the table written on the left of the join predicate. 

17 SQL Query Best Practices Every Developer Should Learn

Hello guys, its no secret that SQL is one of the must have skill in this data driven world and its also one of those skills which is equally useful for programmers, developers, database admins, data scientists, data analyst, business analyst, quality analyst and even project managers. I first learned SQL 20 years back when I was in college and that time we are using Oracle database. I still remember my first query about "SELECT * FROM EMP",  EMP was one of the tables which was quite popular among learners and most of the Oracle DB instance on labs have that. 

Top 12 SQL Query Problems for Coding Interviews (with Solutions)

Hello guys, if you are looking for SQL query examples from interviews or SQL Query Practice questions to improve your SQL skill or just to prepare for tech interviews  then you have come to the right place. Earlier, I have shared best websites to learn SQL and Practice Query online and in this article, I am going to share 12 popular SQL query questions from interviews. SQL is an important skills for both programmers and data scientist, even people from QA and BA stream also need to know SQL to do their job well in this era or data driven world. That's why SQL queries are also quite popular on interviews. 

12 Intermediate Database Administrator and Developer Interview Questions on Indexing

A good understanding of Index is very important for any programmer working with database and SQL. It doesn't matter whether you are working as DBA or Application developer, working in Oracle, MySQL, or Microsoft SQL Server or any other database, you must have good understanding of how index works in general. You should know different types of index and their pros and cons, how your database or Query engine chooses indexes and the impact of table scan, index scan, and index seek. You should also be able to build upon your knowledge to optimize your SQL queries as well as troubleshoot a production issue involving long running queries or poor performing queries. This is also a great skill for experience developers with 5 to 6 years of experience under his belt. 

The 2024 Database Administrator RoadMap

The database administrator is one of the most in-demand jobs nowadays since companies need someone who manages and maintains the infrastructure of their database where they store all their sensitive data. It is expected to grow eight percent from 2020 to 2030, with more than 13,000 opening jobs every year. This article will show you the roadmap to becoming a database administrator.

Top 6 Advanced SQL Books for Experienced Programmers - Best of lot, Must read

If you an experienced programmer and know how to write SQL queries and database fundamentals but want to take your SQL and database skills to the next level then you have a come to the right place. In this blog, I have shared a lot of free SQL books and courses you can use to start your SQL journey. This is also the second article about SQL books, In the first part, I have shared some of the best SQL books which are essential to learning SQL queries and fundamentals of database like normalization, indexing, and other design stuff, if you haven't read it yet, I suggest to do it now. You will find some amazing books to start learning SQL.

Top 5 NoSQL Databases Programmers Should Learn in 2024 [UPDATED]

Though it's not mandatory for Java or Web developers to learn the NoSQL database, the world is moving in that direction, and both Java and Web developer should be familiar with NoSQL databases. If you are wondering what a NoSQL database is means, then here is a quick overview. A NoSQL database refers to non SQL, non-relational, or not only SQL) that provides a mechanism for storage and retrieval of data, which is modeled in means other than the tabular relations used in relational databases. With Spring 5 introducing Web-Flux, a new non-blocking web framework, the use of a NoSQL database will only grow, but the big question is which NoSQL database to start with?

Difference between Oracle SQL Query vs Microsoft SQL Server or Sybase? Answer

Oracle and Microsoft SQL Server are two of the most popular database but they are very different from each other and if you are migrating SQL queries or databases, tables from Oracle database to Microsoft SQL Server 2008 then you are bound to face some issues. The main reason for these porting issues are features that are supported and exists in the Oracle database, but not available in Microsoft SQL Server 2008 like SEQUENCE, Order by clause in subqueries, and derived tables, derived table without a name, etc. I am sure there are a few more and they will surface based upon different database objects you are using in your tables and queries.

How to find duplicate records in a table on database - SQL tips

How to find duplicate records in a table is a popular SQL interview questions which have been asked as many times as difference between truncate and delete in SQL or finding second highest salary of employee. Both of these SQL queries are must know for any one who is appearing on any programming an interview where some questions on database and SQL are expected. In order to find duplicate records in the database table you need to confirm the definition of duplicates, for example in below contact table which is suppose to store name and phone number of the contact, a record is considered to be duplicate if both name and phone number is the same but unique if either of them varies.

How to find second highest or maximum salary of Employee in SQL - Interview question

How to find the second highest or second maximum salary of an Employee is one of the most frequently asked SQL interview questions similar to finding duplicate records in table and when to use truncate vs delete. There are many ways to find second highest salary based upon which database you are using as different database provides different feature which can be used to find the second maximum or Nth maximum salary of employee. Well this question can also be generalized with other scenario like finding second maximum age etc. In this SQL tutorial we will see different example of SELECT SQL query to find second highest salary independent of databases or you may call in ANSI SQL and other SQL queries which uses database specific feature to find second maximum salary.