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.
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.
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:
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!
While working with crude information, you may oftentimes confront date values put away as text. Changing these qualities over completely to a date information type is vital since dates might be more significant during examination. In SQL Server, switching a string over completely to date can be accomplished in various methodologies. In this article, we will cover various techniques to convert String to Date in all databases.
ALTER clause is one of the DDL commands which allows you to change object structure in database like table, stored procedure, trigger, or any other object in the database. By using ALTER command you can add or remove columns in a table, you can add and remove index from a table as well as you can update a stored procedure. ALTER command is an essential SQL commands for programmers similar to SELECT, UPDATE, and DELETE. If you know how to create a table or index then you should also know how to modify a table or index using ALTER command. In this article, we'll see some common ALTER table examples in SQL to learn this command better and become a better database developer.
Hello folks if you want to learn about Stored Procedures in SQL and how it can help you to create a layer of abstraction around functionality then you have come to the right place. With the help of many examples, we will learn how to construct stored procedures in SQL Server.
Hello guys, if you are wondering whether to choose a NoSQL database like MongoDB, Cassandara, or MySQL for your application then you have come to the right place. In an earlier article, MySQL vs PostgreSQL I had shared the pros and cons of choosing MySQL over PostgreSQL for your application, and in this article, I am going to show the benefits and drawbacks of choosing MySQL over NoSQL or vice-versa.
Hello guys, in the past, I gave you a quick overview of SQL JOINS where we learned about different types of JOINS like right, left, inner, and outer join, and in this article, we'll learn about the SQL CROSS JOIN idea in this post, and we'll back up our knowledge with simple examples and illustrations. So, let's start with the basics.
What are SQL commands?
After writing some SQL code, you're ready to query your database. You type in the code, and nothing happens. Instead, you're presented with an error notice.
Don't give up! SQL, like any other computer language, is prone to coding mistakes. We'll go through a few frequent mistakes individuals make while creating SQL in this tutorial.
If you've ever dealt with databases, you've almost certainly come across the term - primary key (PK). And if you're following this series to learn about databases, this piece should help you understand what the PK is all about. Even if you're a database specialist, you could learn something new or improve your skills. So sit back, relax, and let's get started with the PKs.
Hello guys, welcome to my new blog SQLrevisited. I have long back created this blog to exclusively share SQL and Database articles but never get time to start it until today. This is the first article on this blog and in this post, you will learn how to contact multiple columns in an SQL server.
Like Java and many other programming languages and databases, you can use the + operator to concatenate multiple columns in SQL Server. You can join as many columns as you want with the + operator but you must remember that concatenating with NULL will produce NULL, which means you can lose the information from other columns if one of them is NULL.
