What are the 20 basic SQL commands?

SQL (Structured Query Language) is a powerful programming language used for managing and manipulating data in relational database systems. Whether you’re a beginner or an experienced developer, it’s essential to have a solid understanding of the basic SQL commands. In this article, we will explore the 20 fundamental SQL commands that form the building blocks of interacting with databases effectively.


In today’s data-driven world, managing vast amounts of information is crucial for organizations of all sizes. SQL provides a standardized way to store, retrieve, and manipulate data in databases. By learning the basic SQL commands, you’ll gain the foundation to work with databases efficiently and perform tasks such as retrieving specific information, inserting new data, updating existing records, and more.

What is SQL?

SQL, or Structured Query Language, is a domain-specific language used for managing relational databases. It provides a set of commands and syntax that allows users to interact with databases effectively. SQL commands are categorized into different types, such as Data Definition Language (DDL), Data Manipulation Language (DML), Data Control Language (DCL), and Transaction Control Commands.

Importance of SQL in Database Management

SQL is widely used in database management systems due to its simplicity, versatility, and compatibility across various platforms. Whether you’re working with MySQL, Oracle, SQL Server, or PostgreSQL, SQL commands remain consistent with minor variations. This consistency makes it easier to switch between database systems and ensures a broad range of applicability for developers.

Basic SQL Commands Overview

Before diving into the 20 basic SQL commands, let’s briefly explore the core commands that form the foundation of SQL.


The SELECT command retrieves data from one or more tables based on specified conditions. It allows you to retrieve specific columns or all columns and apply filtering criteria to narrow down the results.


The INSERT command is used to add new records into a table. It enables you to specify the values for each column or insert data from another table.


The UPDATE command modifies existing records in a table. It allows you to change the values of specific columns based on specified conditions.


The DELETE command removes one or more records from a table based on specified conditions.

Data Definition Language (DDL) Commands

DDL commands are used to define and manage the structure of database objects. Let’s explore three essential DDL commands.


The CREATE TABLE command creates a new table in the database. It specifies the table name, column names, data types, and any constraints or indexes.


The ALTER TABLE command allows you to modify the structure of an existing table. You can add or drop columns, modify column properties, and more.


The DROP TABLE command deletes a table and its associated data from the database.

Data Manipulation Language (DML) Commands

DML commands are used to manipulate data within the tables. Here are four crucial DML commands.


The SELECT command, as mentioned earlier, retrieves data from one or more tables based on specified conditions.


The INSERT command, also mentioned before, adds new records into a table.


The UPDATE command modifies existing records in a table.


The DELETE command removes one or more records from a table.

Data Control Language (DCL) Commands

DCL commands are used to control access to data within the database. Let’s explore two essential DCL commands.


The GRANT command allows users to grant specific privileges to other users or roles.


The REVOKE command revokes previously granted privileges from users or roles.

Transaction Control Commands

Transaction control commands manage the integrity and consistency of the data within a transaction. Let’s explore three crucial transaction control commands.


The COMMIT command permanently saves the changes made within a transaction to the database.


The ROLLBACK command undoes the changes made within a transaction, reverting the data to its previous state.


The SAVEPOINT command sets a point within a transaction to which you can later roll back.

Constraints and Joins

Constraints and joins are important concepts in SQL. Let’s explore them briefly.

Constraints in SQL

Constraints are rules defined on columns or tables that enforce data integrity and maintain consistency. Common constraints include primary key, foreign key, unique, and not null.

Types of Joins

Joins allow you to combine rows from two or more tables based on related columns. Common join types include inner join, left join, right join, and full outer join.

Sorting and Filtering Data

Sorting and filtering data is crucial when working with large datasets. SQL provides several commands for these tasks.


The ORDER BY command sorts the result set based on specified columns, either in ascending or descending order.


The WHERE command filters the result set based on specified conditions.


The LIKE command is used for pattern matching within the WHERE clause. It allows you to search for specific patterns in text data.

Grouping and Aggregating Data

Grouping and aggregating data enable you to summarize information based on specific criteria. Let’s explore these commands.


The GROUP BY command groups the result set based on specified columns, allowing you to perform aggregate functions on each group.


The HAVING command filters the result set based on conditions applied to the grouped data.


These aggregate functions allow you to count rows, calculate the sum, average, maximum, and minimum values within a group.

Modifying Table Structure

Modifying the structure of a table is sometimes necessary. SQL provides commands to alter table structure easily.


The ALTER TABLE command, as mentioned earlier, allows you to modify an existing table’s structure.


The ADD COLUMN command adds a new column to an existing table.


The MODIFY COLUMN command changes the properties of an existing column.


The DROP COLUMN command removes a column from an existing table.

Indexes and Views

Indexes and views enhance the performance and usability of databases. Let’s explore them briefly.

Indexes in SQL

Indexes improve the retrieval speed of data by creating a quick reference to specific columns or combinations of columns.

Views in SQL

Views are virtual tables derived from one or more tables. They allow you to simplify complex queries and provide a customized view of the data.

Subqueries and Derived Tables

Subqueries and derived tables allow you to perform advanced queries and achieve more complex results. Let’s explore them briefly.

Subqueries in SQL

Subqueries are queries nested within another query. They allow you to retrieve data based on the results of an inner query.

Derived Tables in SQL

Derived tables, also known as subquery results, are temporary tables generated by the result of a subquery. They can be used as regular tables in subsequent queries.


In conclusion, mastering the 20 basic SQL commands discussed in this article is crucial for anyone working with databases. Whether you’re a developer, analyst, or database administrator, having a solid understanding of SQL commands will empower you to interact with databases efficiently and perform a wide range of data manipulation tasks. Remember to practice these commands in a development environment to enhance your SQL skills and become proficient in database management.


Q: What is the purpose of SQL? A: SQL allows users to manage and manipulate data in relational databases. It provides a standardized way to store, retrieve, and modify data, making it a fundamental tool in database management.

Q: Are SQL commands case sensitive? A: SQL commands are generally not case sensitive. However, it’s a best practice to write SQL commands in uppercase to improve readability and avoid potential conflicts.

Q: Can SQL commands be nested? A: Yes, SQL commands can be nested. This allows you to create complex queries by incorporating subqueries within other queries.

Q: How can I learn SQL commands? A: Learning SQL commands can be done through various resources such as online tutorials, courses, and practice exercises. Working on real-world projects and experimenting with databases will also help solidify your understanding of SQL.

Q: What are some advanced SQL commands? A: Some advanced SQL commands include UNION, INTERSECT, EXCEPT, JOIN with different types (e.g., CROSS JOIN, SELF JOIN), and complex subquery usage. These commands expand the capabilities of SQL for handling complex data manipulation tasks.