SQL

SQL, more formally known as “Structured Query Language”, is a language designed to manage data held in a relational database management system.

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24 Results
  • Tutorial

    How To SELECT Rows FROM Tables in SQL

    One of the most fundamental parts of working with databases is the practice of retrieving information about the data held within them. In relational database management systems, any operation used to retrieve informat...
    By Mark Drake SQL Databases
  • Series: How To Use SQL

    How To Update Data in SQL

    When working with a database, there may be times when you need to change data that's already been inserted into it; you may need to correct a misspelled entry, or perhaps you have information to add to an incomplete r...
    By Mark Drake SQL Databases
  • Tutorial

    How To Use WHERE Clauses in SQL

    In Structured Query Language (SQL) statements, WHERE clauses limit what rows the given operation will affect. This guide will go over the general syntax used in WHERE clauses. It will also outline how to combine multi...
    By Mark Drake SQL Databases
  • Tutorial

    How To Modify Items in a One-to-Many Database Relationships with Flask and SQLite

    Flask is a framework for building web applications using the Python language, and SQLite is a database engine that can be used with Python to store application data. In this tutorial, you'll modify items in an applica...
    By Abdelhadi Dyouri Flask Python Python Frameworks SQL Databases SQLite
  • Tutorial series

    How To Use SQL

    Series Description Structured Query Language (https://en.wikipedia.org/wiki/SQL) — commonly known as SQL — is a language used to define, control, manipulate, and query data held in a relational database. SQL has been ...
    By Mark Drake Databases Conceptual SQL
  • Tutorial

    What is MariaDB?

    MariaDB is an open-source relational database management system. As with other relational databases, MariaDB stores data in tables made up of rows and columns. Users can define, manipulate, control, and query data usi...
    By Mark Drake Glossary MariaDB Databases SQL
  • Series: How To Use SQL

    How To Insert Data in SQL

    SQL provides a great deal of flexibility in terms of how it allows you to insert data into tables. You can specify individual rows of data with the VALUES keyword, copy entire sets of data from existing tables with SE...
    By Mark Drake Databases SQL
  • Series: How To Use SQL

    How To Delete Data in SQL

    As the name implies, DELETE operations irreversibly delete one or more rows of data from a database table. Being such a fundamental aspect of data management, it's important for SQL users to understand how the DELETE ...
    By Mark Drake Databases SQL
  • Tutorial

    How To Install OpenEMR on Ubuntu 20.04 with a LAMP Stack (Apache, MySQL, PHP)

    In this tutorial, you will install OpenEMR on Ubuntu 20.04 along with its dependencies Apache, MySQL, and PHP.
    By Erin Glass SQL LAMP Stack
  • Series: How To Use SQL

    How To Use Wildcards in SQL

    Like many computer languages, SQL allows the use of various wildcard characters. Wildcards are special placeholder characters that can represent one or more other characters or values. This is a convenient feature in ...
    By Mark Drake Databases SQL
  • Tutorial

    How To Use the BETWEEN and IN Operators in SQL

    In certain Structured Query Language (SQL) statements, WHERE clauses can be used to limit what rows the given operation will affect. SQL allows users to retrieve granular result sets by providing a variety of differen...
    By Mark Drake SQL Databases
  • Tutorial

    What is the Relational Model?

    The relational model is an abstract model used to organize data within a database. In order to control access to a database, write data, run queries, or perform any other tasks related to database management, a databa...
    By Mark Drake Databases Glossary SQL
  • Tutorial

    How To Use Comparison and IS NULL Operators in SQL

    In certain Structured Query Language (SQL) statements, WHERE clauses can be used to limit what rows the given operation will affect. SQL allows users to retrieve granular result sets by providing a variety of differen...
    By Mark Drake SQL Databases
  • Series: How To Use SQL

    How To Use Joins in SQL

    Many database designs separate information into different tables based on how certain data points relate to one another. Even in cases like this, it's likely that there will be times when someone will want to retrieve...
    By Mark Drake Databases SQL
  • Tutorial

    What is SQL?

    Structured Query Language — commonly known as SQL — is a language used to define, control, manipulate, and query data held in a relational database.
    By Mark Drake SQL Glossary
  • Series: How To Use SQL

    Understanding SQL Constraints

    Relational database management systems allow you to control what data gets added to a table with constraints. A constraint is a special rule that applies to one or more columns — or to an entire table — that restricts...
    By Mark Drake Databases SQL Conceptual
  • Series: How To Use SQL

    How To Use Constraints in SQL

    When designing an SQL database, there may be cases where you want to impose restrictions on what data can be added to certain columns in a table. SQL makes this possible through the use of constraints. After applying ...
    By Mark Drake SQL Databases
  • Series: How To Use SQL

    How To Create and Manage Tables in SQL

    Tables are the primary organizational structure in SQL databases. They consist of any number of columns, which reflect individual attributes of each row, or record, in the table. Being such a fundamental aspect of dat...
    By Mark Drake Databases SQL
  • Question

    MySQL Managed Database can't modify database without setting primary key, but I can't set primary key without modifying the database.

    Hi, so I currently have a table with the following datatypes: column1 -> TEXT column2 -> TEXT column3 -> TEXT This table is huge, with over 500k+ rows. When I initially started using MySQL on DO, I hardly knew what a ...
    Accepted Answer: Hi @miramallows You can use the SET SESSION sqlrequireprimary_key = 0; It is for a single session though. Once you log out, you would need to run this again before you could do modify the table without primary key. T...
    1 By miramallows DigitalOcean Managed MySQL Database MySQL SQL
  • Question

    What's the easiest way to setup automatic nightly SQL script executions?

    Hi there, I was wondering how I could most easily setup nightly SQL script executions using the RDBMS here. I'm hoping to build a MySQL or Microsoft SQL Server database (as I learned how to use these in college) here ...
    Accepted Answer: Hi @nirox, My suggestion would be for you to use cron jobs. The cron jobs should be executed at night whenever you want and they should be scripts. In these scripts, you can specify what database queries to be done. I...
    1 By niroxu MySQL SQL