Types of SQL Commands (DDL, DQL, DML, DCL, TCL) - SQL Tutorial #5

Learn the main types of SQL commands including DDL, DQL, DML, DCL, and TCL, essential for database management and querying.

Key Takeaways

SQL commands are categorized into five main groups based on their function: DDL, DQL, DML, DCL, and TCL.
DDL commands modify database structure, DQL retrieves data, and DML manipulates data within tables.
DCL commands manage user access and permissions, while TCL commands control transaction integrity.
Mastering the SELECT command is crucial for effective SQL querying.
Understanding these command groups helps in organizing and writing efficient SQL scripts.

What the video covers

Introduction to the main SQL command groups and their purposes.
Explanation of Data Definition Language (DDL) commands like CREATE, DROP, and ALTER for database structure changes.
Overview of Data Query Language (DQL) focusing on the SELECT command for data retrieval.
Details on Data Manipulation Language (DML) commands such as INSERT, DELETE, and UPDATE for managing data.
Description of Data Control Language (DCL) commands GRANT and REVOKE for managing user permissions.
Introduction to Transaction Control Language (TCL) commands like COMMIT, ROLLBACK, and SAVEPOINT for transaction management.
Advice on the importance of mastering SELECT statements for SQL proficiency.
Clarification that memorizing command group names is not mandatory except for DDL in project contexts.
Outline of the tutorial focus on the first three command groups: SELECT, DDL scripts, and DML commands.
Mention of additional free SQL materials available in the video description.

Chapters

What are the main groups of SQL commands?

SQL commands are divided into five main groups based on their purpose: Data Definition Language (DDL), Data Query Language (DQL), Data Manipulation Language (DML), Data Control Language (DCL), and Transaction Control Language (TCL).

Which SQL command is most important to master for querying data?

The SELECT command, which belongs to the Data Query Language (DQL) group, is the most important command to master for retrieving data from a database.

What is the purpose of DCL commands in SQL?

Data Control Language (DCL) commands like GRANT and REVOKE are used to manage user permissions and access rights to database objects such as tables and schemas.

Full Transcript — Download SRT & Markdown

Speaker A

[Music] All right, so now let's talk about SQL commands. In SQL, we have around 12 main commands and 900 different keywords. Of course, I will not be explaining all of them. Instead, in our tutorials, I will be focusing on the most used SQL commands and statements that I use in my projects in the last 10 years. To make our life easier, SQL commands are divided into different groups depending on their purposes. Alright, let's start with the first group: Data Definition Language, DDL.

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As the name suggests, here you will find all the commands that allow you to define your database, like creating tables, dropping columns, changing tables, anything that's going to change the structure of your database. Underneath this group, you can find commands like

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CREATE, which helps you to create anything new in the database, like creating a new table, creating a new view, stored procedures, and so on. One more, we have here the DROP commands that allow you to delete one object from your database, and

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the last one, ALTER. It helps you to edit the structure of your database, like altering one table to change a column or to add a new column. Okay, so now to the second group, we have Data Query Language, DQL. It contains only one command, and

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that's enough. It's called the SELECT command. SELECT helps you to retrieve your data from your database. SELECT is the most important command that we have in SQL and the one that you need to master in order to be good in SQL. In my

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tutorials, I will be explaining everything about the SQL SELECT statements because if you start working with SQL, you will end up writing tons of SELECT statements. So don't worry about it. Alright, let's go now to the next group. We have Data Manipulation

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Language, DML. DML contains all the SQL commands that you could use in order to manipulate your data inside your database. So we have commands like INSERT in order to insert new data inside your tables, or we have DELETE to delete some

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data from your tables, or UPDATEs to update the content of existing data inside tables. So as you see, it is really easy. The names tell everything. Alright, so now we have two groups of commands that are really more for SQL database

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administrators. So the next one we have is Data Control Language, DCL. DCL contains SQL commands that allow you to give access to a specific user to your database or to tables or schemas and so on. So here we have two commands: GRANTs you

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could use GRANTs to give someone access to your objects in databases or REVOKE to remove such access from a specific user. Okay, so now to the last group that we have, the Transaction Control Language, TCL. In TCL, you will

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find the SQL commands that are going to help you to manage the database transactions in order to maintain the integrity of your data. So here we have commands like COMMITs in order to save the changes in your database, ROLLBACK

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to restore the database to the last commit or to the last savepoint if you have some errors. You could use that savepoint. You can define savepoints in the transactions which you could use later to roll back. All right, so now

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about those names: DDL, DQL, DCL, TCL, and so on. You don't have to memorize them, maybe only the important one is DDL. Sometimes you hear it in the project, so if someone says, "I will be creating some DDL scripts," that means he or she is going to

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create SQL statements to change the structure of the database, like creating a new table or dropping something. All right, so in our SQL tutorials, we will be focusing on the first three groups of the SQL commands. We will start with the

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most famous one, the SQL SELECT statements, and after that, we're going to deal with all those DDL scripts, and finally, I'm going to explain INSERT, DELETE, and UPDATEs. Alright, so that was the main types of SQL commands. Next, you will

Speaker A

learn the basic elements of SQL statements. And if you like this video, I might work and you want to support the channel, then subscribe, like, and comment. And in the video description, you will find a link to free SQL materials like

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the database and the data of this tutorial, the SQL cheat sheets, and as well all the presentations. Thank you so much for watching, and I will see you in the next tutorial. Bye. Foreign [Music]

Speaker A

the database and the data of this tutorial the SQL sheet cheats and as well all the presentations thank you so much for watching and I will see you in the next tutorial bye foreign [Music]

Topics:SQLSQL commandsDDLDQLDMLDCLTCLSQL tutorialdatabase managementSQL SELECT

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