What Are SQL Queries?

Key takeaways

• SQL queries, such as data query language and data definition language, help you access, manipulate, and analyze data efficiently.

• Basic SQL queries include data manipulation language, which helps you modify information in a database, and data control language, such as GRANT or REVOKE, which control access rights.

• SQL queries are useful across industries for creating databases, retrieving data, controlling access to data, and updating database structures.

To write SQL queries, use commands like DELETE to remove rows from a table or CREATE to develop new database tables. Explore different types of SQL queries and when to use them in this article. If you’re ready to develop your skills, consider enrolling in the Meta Database Engineer Professional Certificate. You’ll have the opportunity to learn how to demonstrate proficiency in SQL syntax and create databases from scratch in as little as six months. By the end, you’ll have earned a shareable career credential for your resume.

Types of SQL queries

SQL (structured query language) has specific language types for commands that developers use, including data query, data definition, data manipulation, data control, and transaction control languages. SQL is a universal computer language used to manage relational databases, which businesses use to store data in tables of columns and rows. Using English-like commands, SQL queries allow users to access, manipulate, and analyze data efficiently. Understanding SQL queries is essential for anyone interested in data analysis, database management, or uncovering business insights through data.

To begin your learning journey, consider becoming familiar with some of these basic SQL languages and queries:

Data query language

You can use data query language (DQL) statements to collect specific data from a database. DQL includes one primary command: SELECT. This command specifies which columns and rows to retrieve data from.

Data definition language

You can use data definition language (DDL) statements to create, name, change, declare, or destroy objects within a database. DDL focuses on designing or updating the overall database structure. These commands auto-save in the database and include the following:

• ALTER: Modifies existing objects

• CREATE: Establishes new database tables, including names, sizes, and properties

• DROP: Deletes entire structures and tables and the data inside them

• RENAME: Creates a new name for existing structures

• TRUNCATE: Removes records from a table without removing the structure

Data manipulation language

Data manipulation language (DML) statements allow developers to write and modify information in a database. You cannot reverse these commands since they don’t automatically save. DML commands include the following:

• DELETE: Removes rows from a table

• INSERT: Adds rows to an existing table

• UPDATE: Changes the row values in an existing table

Data control language

To control specific user access to a database, you will use data control language (DCL) statements. These commands can apply certain access rights or restrictions for groups of users, such as granting the ability to view or update a table. To do this, you would use either a GRANT or REVOKE command:

• GRANT: Provides a user with certain privileges for tables

• REVOKE: Removes a user’s privileges

Transaction control language

Using transaction control language (TCL) statements allows for managing transactions within a database. Transactions refer to a sequence of SQL statements that apply concurrently to the database to ensure consistency. Three main commands make up TCL, including:

• COMMIT: Ends the current transaction and permanently saves all changes

• ROLLBACK: Reverses changes you made during a transaction

• SAVEPOINT: Sets a point you can return to within a transaction

SQL processing

For a system to execute a SQL query, it first needs to process it. SQL queries go through four main phases:

1. Parsing: Verifies the query and formats it for a computer to process

2. Optimization: Generates the most efficient execution plan to retrieve data

3. Row source generation: Produces the execution plan used for the database

4. Execution: Runs the query based on the sequence established in the execution plan

What can you use SQL queries for?

SQL queries have many uses across different industries since many companies rely on properly maintained digital information. Some common uses for SQL queries include creating a database, retrieving data, controlling access to data, and updating a database’s structure.

In general, SQL queries power SQL databases to run financial systems or payment applications, pull business intelligence reports, and securely store data for compliance.

Read more: Why and How to Learn SQL

Pros and cons of SQL queries

Like many technologies, using SQL queries has advantages and disadvantages. Some benefits include the following:

• Quick processing: SQL quickly processes all queries, no matter how large a database is.

• Easy to learn: Since SQL queries use simple commands, you do not need an extensive coding background to understand the basics.

• Commonly used: Many IT systems use SQL, so your knowledge likely will translate across multiple companies. Additionally, SQL is an open-source language, so you can find large networks of support as you learn.

Some disadvantages when using SQL queries include:

• Expensive: Since SQL databases require hardware to increase capacity, upgrades and maintenance can come with high costs.

• Time-consuming setup: Before anything else, you must appropriately structure the data for a new database, which can take some time.

Who uses SQL queries?

Many positions across various industries use SQL queries. Software or computer professionals commonly use SQL queries to ensure relational databases properly communicate with websites or applications. However, many other types of professionals benefit from using SQL queries to access, analyze, and interpret data for various companies.

According to the US Bureau of Labor Statistics, you can expect data-related occupations to grow faster than average for all occupations; for example, data scientists will grow by 35 percent between 2025 and 2035 [1]. A few data-related roles that commonly use SQL include the following:

All salary information represents the median total pay from Glassdoor as of September 2026. These figures include base salary and additional pay, which may represent profit-sharing, commissions, bonuses, or other compensation.

1. Data analysts

Median annual US salary (Glassdoor): $94,000 [2]

Since data analysts perform various duties related to data systems and databases, knowing the SQL language is key to their role. While the exact responsibilities for this role depend on a company’s needs and practices, you would generally collect and analyze data, perform research, and prepare reports that businesses use to make critical decisions.

2. Database administrators

Median annual US salary (Glassdoor): $107,000 [3]

Database administrators organize and manage databases that store secure data for various business needs. In this role, you would also optimize databases to make them more accessible and secure, and ensure authorized users can access certain data sets. Since this position relies on managing databases, you must be proficient in SQL to perform the required duties.

3. Software developers

Median annual US salary (Glassdoor): $123,000 [4]

Many software developers work with applications or programs that need to properly communicate with relational databases, so familiarity with SQL is helpful in this role. As a developer, you’ll likely use SQL queries and commands for your website or application to display information and store user data correctly.

How to get started with basic SQL queries

Whether interested in a web or application development role or other data-related positions, you can learn SQL and SQL queries through online resources, education, and experience.

Education

If you’re interested in pursuing a data-related role, you’ll likely need to earn a bachelor’s degree at a minimum. However, you can also learn SQL through online resources or certifications. Since SQL is an open-source language, you can find many online educational resources, such as video tutorials, to learn basic commands. You can also consider taking courses to gain certifications like Meta's Database Engineer Professional Certificate. Courses allow you to learn through assignments and interactive lessons.

Experience

Some data-related roles may require certain industry experience or certification, but you will likely want to start by learning the basics of SQL or any other technical skills required. Since many companies view SQL as a highly in-demand skill for working with data, learning this skill can increase your job prospects for data-related roles and help you add value to your organization. Knowing SQL may also boost your pay and promotion prospects.

Explore free career resources

Join us on Career Chat, where you can explore industry insights and access helpful career tips. Then, check out these free resources to learn more about a career using SQL:

• Consider your path: SQL Learning Roadmap: Skills, Courses and Topics

• Bookmark this page: SQL Glossary: SQL Terms and Definitions

• Read an insider story: Meet the Data Analyst Using His Creativity to Tell Visual Stories

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