How to Sort or Order results in SQL query? ORDER BY Example Tutorial

Ordering results in SQL is a fundamental aspect of retrieving and presenting data in a meaningful way. When querying a database, the order in which the results are displayed can significantly impact the user's understanding of the information. The SQL ORDER BY clause provides a powerful mechanism to sort query results based on one or more columns in ascending or descending order. Whether you are working with a small dataset or a large database, understanding how to order results allows you to tailor the presentation of information to meet specific requirements. 

How to add/remove and modify column in a table?

 Hey there! Today, I'm going to share some DB wizardry that's incredibly handy in your SQL adventures: how to add, remove, and modify columns in a database table. Whether you're a seasoned data sorcerer or just starting your magical journey, this article has something for everyone.

How to store and Query Hierarchical Data in Database using SQL? Example Tutorial

What methods do you use to detect hierarchical data and query it? We're about to get answers to two popular SQL queries. When working with SQL and relational databases, querying hierarchical data is a typical occurrence. It's not that hierarchical data is mysterious or uncommon; on the contrary, it's all around us. So, why is hierarchical data so difficult to work within relational databases? The issues arise mostly when converting hierarchical data to relational database concepts.

Top 30 Database Interview Questions and Answers

 Hello guys, if you are preparing for programming or technical interview then you must prepare for Database and SQL, these two are the most important skill for any programming or software development job be it a Java developer, C++ developer or a web developer. Earlier, I have shared 15 SQL Query Interview Questions and in this article, I am going to share 30 common database interview questions. I am not sharing the answer though as I expect you to already know the answers of these basic Database questions but if you struggle with any questions, ping me on comments section and I might just add the answers as well, depending upon what you guys like. 

How to create and Rollback Transaction in SQL query? Example Tutorial

A transaction in SQL Server is a consecutive gathering of explanations or queries to perform single or numerous undertakings in a data set. Every transaction might have single perused, compose, update, or delete tasks or a blend of this large number of tasks. Every transaction should happen two things in SQL Server:

• Either all alteration is effective when the transaction is committed.
• Or on the other hand, all alterations are scattered when the transaction is rollback.

Difference between DELETE vs DROP vs TRUNCATE in SQL

What the differences are between the commands Delete, Drop, and Truncate has to be one of the most popular queries during SQL interviews. We are here to answer any of your questions regarding this interview question. In this article, we will go over this concept and learn the difference between them in a very practical manner. So, what's the wait? let's start!

How to find top 10 records from a table in Oracle, MySQL, and SQL Server? Examples

Finding top 10 records is common need for programmers working with tables and database. Be it courses, cars, cricket, players, etc. The list is never-ending. But how do select TOP records from the database? As this is what happens in the back-end. So, if you are also looking for the answer to this question, check out this article and know more. We will see how to select the TOP 10 records from different databases with practical examples.

Difference between UNION and UNION ALL in SQL

Hello guys, if you are wondering how to combine data from multiple tables into one result set in SQL then there are multiple options. Earlier, we have looked at JOIN which allows you to fetch data from multiple table in single query, other option is UNION and UNION ALL which you can use to combine the data from multiple tables. We saved data in SQL tables in the relational database. We may need to choose data from various tables and aggregate the results of all Select statements on occasion. The SQL Union and versus Union All operators in SQL Server are explained in this article. We'll also look at the differences between these two operators, as well as some applications.

How to do Pagination in SQL Server? Query Example Tutorial

 What is pagination?

Pagination, often known as paging, is a method of breaking down huge amounts of material into smaller, distinct pages. Pagination is a popular feature of online applications, as evidenced by Google. The primary principle of pagination is that when we search for anything on Google, the results are displayed on a different page.

Transposing data in SQL - Example Tutorial

What is Transposition?

A transposition is when data is rotated from one row or column to another in order to modify the data layout and make observations from a different perspective. Row to the column, column to column, and bidirectional transposition are examples of basic transposition algorithms. Others, such as dynamic transposition, transposition with inter-row computations, and join-based transposition, are more complicated. All are prevalent in data analytics and so worthy of investigation.

Difference between DDL and DML commands in SQL with examples

What are SQL commands?

SQL commands are just that: commands. It's used to send and receive data from the database. It may also be used to carry out particular activities, functions, and data searches.

SQL can build tables, add data to tables, drop tables, change tables, and define permissions for users, among other things.

MySQL vs PostgreSQL? Pros and Cons

When establishing a new project, especially one on the Web, choosing a database management system is frequently an afterthought. Most frameworks include an object-relational mapping (ORM) tool that hides the differences across platforms and makes them all run at the same speed.

What is Virtual columns in MySQL and How to use it? Example Tutorial

 What is a Virtual Column and where is it used?

Virtual/generated columns are a new feature in MySQL 5.7. Because the data in this column is computed based on a specified expression or from other columns, it is called a generated column.

Virtual columns resemble regular table columns in appearance, but their values are generated rather than saved on a disc.

Virtual columns are one of MySQL 5.7's most useful features; they allow you to store a value in a new field that is derived from one or more other fields in the same table.

How to filter data in SQL? WHERE, LIKE, and BETWEEN Example

In SQL, you can filter data using the WHERE clause in your queries. The WHERE clause allows you to specify a condition that must be met for a row to be included in the result set. You can use basic conditional operator, logical operator to filter based upon any condition as well as LIKE operator filter based upon any pattern. You can also filter on rang using IN and BETWEEN clause whose examples we will see in this article. 

Difference between Primary and Foreign key in Database and SQL

Hello guys, if you are preparing for database or developer interview then questions form primary key is very common on interviews. One of such question is primary key vs foreign key which is asked ot me multiple times during early stage of my career. Now my experience has grown so I don't see this question quite often but the concept is still very important for any database admin or programmer to understand. 

The key difference between primary key and foreign key is that primary key on one table can be foreign key on other related table. 

For example, you have two tables Employee and Department, each have primary key emp_id and dept_id, now if you want to link or join these two table then you created a column called dept_id on employee table to indicate which department a particular employee work and now dept_id is a foreign key in Employee table. 

Top 50 Database and SQL Interview Questions Answers for 2 to 5 Years Experienced

 Hello guys, whether you are preparing for Java developer interview or any other Software Developer Interview, a DevOps Interview or a IT support interview, you should prepare for SQL and Database related questions. Along with Data Structure, Algorithms, System Design, and Computer Fundamentals, SQL and Database are two of the essential topic for programming or technical Job interview. In the past, I have shared many questions related to MSSQL questions, Oracle Questions, MySQL questions, and PostgreSQL questions and in this article, I am going to share both theory based and query based Database and SQL Interview questions with to the points answers.

Difference between 1NF, 2nd NF, 3rd NF and BCNF? Normalization Example Tutorial

Normalization is one of the essential concept of relational database. It is the process or technique to remove duplicate data from tables and thus reduce the storage size. It also helps to maintain integrity of data. Normalization likewise assists with coordinating the information in the data set. It is a multi-step process that sets the information into even structure and eliminates the copied information from the relational tables. 

Difference between Primary key vs Unique key in a Table

The primary key and unique key are two important concepts in a relational database and are used to uniquely identify a row in a table. Both primary key and unique keys can identify a row uniquely but there is some subtle difference between them which we will see in this article. In fact, primary key vs unique is a popular SQL interview question along with classics like truncate vs delete and  How to manage transactions in a database, mostly asked to fresher and 2 to 3 years experience guys in any programming language. 

Difference between Primary key Unique key in Database SQL

Hello friends, both primary key and unique key are two important concepts in a relational database which are used to uniquely identify a row in a table. For example, EmployeeId is often primary key in Employee table which can uniquely identify any employee which is denoted by a row in Employee table. Similarly, a employee can also be identify with EmployeeName if there is no duplicate but if its not primary key then we call it a unique key. While both primary key and unique keys can identify a row uniquely but there is some subtle difference between them which we will see in this article. 

What is NULL in SQL? How to use Nulls in Query? Example Tutorial

Hello guys, NULL is a very important concept in SQL as it indicate absence of values. A column can be Nullable or not Nullable, which means it can either contains null values or not. For a column which contains optional values like Car in Person table, you can use Null to indicate a person doesn't have car. 

While this part is easy, the real trouble comes when you need to query and deal with values which may have nulls. For an SQL developer it's important to find all rows where a certain column is Null, now how to compare Null as simply checking with = or != is not enough. 

This article will describe the complications that might arise when working with SQL NULL values, as well as some tips for resolving them.