In relational databases, the SQL ORDER BY statement is a powerful tool for sorting data in a table. The statement is used to arrange queried data into rows in a specific order, based upon one or more columns. In this database programming tutorial, we will learn how to use the SQL ORDER BY statement to sort retrieved data in ascending or descending order. Read: Best Courses for Database Administrators SQL ORDER BY Statement Syntax The syntax for the SQL ORDER BY statement is shown in the following example code: SELECT columnA, columnB, columnC FROM table_example ORDER BY columnA, columnB, col ..read more

In SQL and relational databases, NULL values are an important part of managing data and information stored in SQL tables. A NULL value is used as a placeholder for missing values or values that are unknown in a database column or cell. Understanding how to handle NULL values is important for database developers who want to avoid errors and retrieve accurate results when querying a database table. This database development tutorial covers the basics of how to work with NULL values in SQL. Read: Best Online Courses to Learn SQL What is a NULL Value in SQL? In relational databases and RDBMS’, NU ..read more

In a previous tutorial, we learned how to work with the WHERE clause in SQL, which database developers can use when they wish to retrieve a group of records that meet a certain criteria or condition. For instance, a database administrator may wish to find every instance in a database where a user’s name is equal to “Ronnie” – or, more likely, not equal to “Ronnie”. As powerful as the WHERE clause is in SQL, we can make it even stronger when we apply SQL’s NOT, AND, and OR operators. This database development tutorial shows db admins and programmers how to use the NOT, AND, and OR operators in ..read more

In SQL, data types help to define the type of value that can be stored in a database cell, or, more specifically, in a column. There are many kinds of data types in SQL and in this database programming and administration tutorial, we will look at each one and learn their syntax, how to use them, when to use them, their use case, and how they differ in specific relation database vendors, such as MySQL, Oracle, PostgreSQL and MS SQL Server. Before we begin, if you prefer to learn in a classroom or online environment, we have a list of the Top Online Courses to Learn SQL to help you get started ..read more

PostgreSQL is one of the world’s most widely used database systems in the world, offering support for not only structured query language (SQL), but JSON as well, making it a great choice for database-driven enterprise applications. In this database programming and database administration tutorial, we discuss what PostgreSQL is, its relation to SQL, and the benefits of working with the hybrid database system. Read: What is MySQL? Overview of PostgreSQL PostgreSQL, like other offshoots of SQL database systems, is often viewed as a database programming language. However, this is a misnomer, as P ..read more

An SQL injection is an attack on a database server where a malicious actor enters – or injects – some nefarious input in a form, other than the expected input. The attack can be used to gain access to restricted data, wipe out databases, and examine the server info, among other things. In this database programming tutorial, database developers and database administrators will learn a number of ways that a hacker can exploit your database. This database tutorial will also show you how you can protect your application from these vulnerabilities. Read: SQL Best Practices What are the Types of SQ ..read more

In a previous tutorial, we discussed how to use the SQL SELECT statement to return values from a table. In today’s database programming tutorial, we will learn how to use the SELECT DISTINCT statement to return only distinct – or unique – values from a table. You can read about regular SELECT SQL statements in our tutorial: How to Use the SQL SELECT Statement. SQL SELECT DISTINCT Statement and Syntax The SELECT DISTINCT statement is used for cases where you only want to return values that are unique, distinct, or different from one another. For instance, if you have a table with data containi ..read more

If you are new to database administration or database development, you have no doubt heard the phrase “relational database management system” being tossed around. As database programmers or those that work with databases, we tend to think of database systems in terms of languages or platforms, like SQL, MySQL, or T-SQL. In today’s database programming tutorial, we are going to discuss RDBMS systems and answer the question: “What is a Relational Database Management System” and provide some tips for working with one. Read: Top Online Courses for Learning MySQL What is a Database? While this tut ..read more

Structured Query Language (SQL) is a simple, yet powerful database programming and administration language used to manipulate data stored in a relational database or relational database management system (RDBMS). It is easy to learn compared to a lot of traditional programming languages. While that is great for both new database developers and veterans alike, it can lead to issues; since learning the database language is so simple, programmers can often overlook best practices and just dive right in. To avoid this issue, this database programming tutorial will cover the best practices for writ ..read more

Database administrators – or those that handle the administrative tasks associated with running a database system, rely on a database programming language to issue queries to retrieve and manipulate data from their respective database. Database programmers, data analysts, data modelers, and anyone who needs to access the information stored in a relational database management system (RDBMS) use some form of what is known as SQL – or Structured Query Language. In this database development tutorial, we discuss what SQL is, its benefits, and disadvantages. Before we begin learning about SQL, a qu ..read more