DQL Full Form (original) (raw)

Last Updated : 12 Jul, 2025

**Data Query Language (DQL) is a component of **Structured Query Language (SQL) focused on retrieving data from databases using the **SELECT statement.

It allows users to extract specific information based on defined criteria, enabling efficient data analysis and decision-making. In this article, We will learn about the **DQL Full Form in detail by understanding various aspects in detail.

Introduction to Data Query Language (DQL)

• Structured Query Language (**SQL**)** is a **nonprocedural language used for retrieving data from queries. It was introduced by **IBM as a part of the R project. It was declared as a standard language by **ANSI and ISO. **DQL statements are used for performing queries on the data within schema objects.
• The purpose of the DQL Command is to get some schema relation based on the query passed to it.
• We can define DQL as follows it is a component of SQL statement that allows getting data from the database and imposing order upon it.
• It includes the SELECT statement. This command allows getting the data out of the database to perform operations with it.
• When a **SELECT is fired against a table or tables the result is compiled into a further temporary table, which is displayed or perhaps received by the program i.e. a front-end. **Data Query Language (DQL) or **Data Retrieval Language (DRL).

Data Query Language has commands that retrieve the data from the query. It has a single command: select. It has subcategories:

• DDL or Data Definition Language has commands like create, rename, and alter.
• DML or Data Manipulation Language has commands like update, insert, and delete.
• DCL or Data Control Language has commands like grant and revoke.
• TCL or Transaction Control Language has commands like rollback, and commit.

**Characteristics of Data Query Language (DQL)

It is used for retrieving data. A user can retrieve data according to his/her requirements using the select command.

1. **Data Retrieval: DQL is used only to retrieve data.
2. **Flexibility in query: The SELECT statement enables a user to obtain specific data based on criteria or conditions.
3. **Data Ordering: It keeps the results sorted and filtered. This way, work on database data becomes even more structured and organized.
   **Example:
   If a user wants to retrieve all the from the employee table, the query must be given as follows:

select *
from employee;

asterisk mark (*) indicates that all the rows are retrieved from the table.

If a user wants to know the average salary of the employees, the query must be given as follows:

select avg(salary)
from employee;

This displays the average salary of the employees.
Here asterisk mark isn't needed as we need to retrieve only particular rows.

If a user wants to know the name of the employee whose salary is less than 10, 000; the query is:

select ename
from employee
where salary<=10, 000;

A condition is placed to retrieve the data and a relational operator is used as well.

**Advantages of DQL

• SELECT is a standard command used for almost every query.
• It can also be written as SELECT as SQL is a case-insensitive language.
• It makes the data retrieving process easier.
• No coding is needed.
• This domain language can be used for communicating with the databases and receive answers to complex questions in seconds.

**Disadvantages of DQL

• Data Query Language has no disadvantages.
• It is not possible to imagine Structured Query Language without the select command.
• Interfacing a DQL database is more complex than adding a few lines of code.
• The operating cost of some DQL versions makes it difficult for some programmers to access them.

**Applications of DQL

• Analytical Queries.
• Retrieve Information from the database.
• Modify the index structures and database table.
• Such questions are analytical in nature and DQL is used abundantly to run analytical queries in retrieving worthwhile knowledge from data.
• **Database Information Retrieval: This helps in retrieving a certain information from the database for achieving a task, such as employee's details or sales records, etc.
• **Modify Index Structures: DQL creates modifications in database structures. To enable improved queries, indexing is also done.

Conclusion

Lastly, Data Query Language (DQL) is a component of DBMS that can really retrieve data from relational databases using the power that is simple. It allows the user to select query-efficiently with the combination and the application of a basic command: SELECT. Other benefits, such as the simple interfacing and low operating costs of some systems, do offset its limitations.