![]() The SQL syntax includes a number of functions that allow you to interpret or run calculations on your data just by issuing a SELECT query. Rather, you want information about the data. Oftentimes, when working with data, you don’t necessarily want to see the data itself. This is where aggregate functions come into play. These are useful for basic queries, but they aren’t helpful if you’re trying to perform a calculation or derive a scalar value (a single value, as opposed to a set of multiple different values) based on your data. The examples we’ve gone through up to this point include some of the more frequently-used keywords and clauses in SQL queries. Here, we have told SQL to display the name column as n, the birthdate column as b, and the dessert column as d. To begin, open up a MySQL prompt as your root MySQL user: Rather than keep this information in a physical ledger, you decide to exercise your database skills by recording it in a MySQL database. Also, to make planning dinners easier, you decide to create a record of your friends’ birthdays and their favorite entrees, sides, and desserts. Now that this tradition has been going on for a while, you’ve decided to begin tracking the records from these tournaments. On each occasion, the members of the group head to the local bowling alley, participate in a friendly tournament, and then everyone heads to your place where you prepare the birthday-person’s favorite meal. You and several of your friends all celebrate your birthdays with one another. This will allow you to gain some hands-on experience when you begin making queries later on.įor the sample database we’ll use throughout this guide, imagine the following scenario: ![]() Creating a Sample Databaseīefore we can begin making queries in SQL, we will first create a database and a couple tables, then populate these tables with some sample data. With this setup in place, we can begin the tutorial. Our guide on How to Install MySQL on Ubuntu 18.04 can help you set this up. This can be set up using our Initial Server Setup guide for Ubuntu 18.04. ![]() An Ubuntu 18.04 machine with a non-root user with sudo privileges.To set this up, you will need the following: However, it was written specifically with an Ubuntu 18.04 server running MySQL in mind. In general, the commands and concepts presented in this guide can be used on any Linux-based operating system running any SQL database software. It generally follows the ANSI SQL standard, although there are a few cases where MySQL performs operations differently than the recognized standard. One of the most widely-deployed SQL-databases, MySQL prioritizes speed, reliability, and usability. MySQL is an open-source relational database management system. We will also practice making SQL queries using some sample data in a MySQL database. In this guide, we will discuss the basic syntax of SQL queries as well as some of the more commonly-employed functions and operators. In Structured Query Language (SQL), queries are almost always made using the SELECT statement. In relational database management systems, a query is any command used to retrieve data from a table. There are several ways to retrieve information from a database, but one of the most commonly-used methods is performed through submitting queries through the command line. One of the most important aspects of database management is the practice of retrieving data from a database, whether it’s on an ad hoc basis or part of a process that’s been coded into an application. Databases are a key component of many websites and applications, and are at the core of how data is stored and exchanged across the internet.
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