How to Rename Column name in SQL?

What is SQL?

SQL (Structured Query Language) is a powerful and versatile language that is widely used for managing and manipulating data stored in relational databases. It is a standard language used by relational database management systems (RDBMS) to interact with the data stored in a database.

SQL allows you to perform a variety of tasks, including:

• Creating and modifying the structure of a database: You can use SQL to create tables, define columns, set up relationships between tables, and create indexes for faster data retrieval.
• Inserting, updating, and deleting data: You can use SQL to insert new data into a table, update existing data, and delete data that is no longer needed.
• Retrieving data: You can use SQL to retrieve data from a database based on specific criteria. This can be done using SELECT statements, which allow you to specify the columns and rows you want to retrieve and the conditions that must be met for a row to be returned.
• Aggregating data: You can use SQL to aggregate data from multiple rows and summarize it in a meaningful way. This is typically done using functions such as SUM, AVG, COUNT, and MAX.

SQL is a declarative language, which means you specify what you want the database to do, and the database management system takes care of figuring out how to perform the task. This makes SQL relatively easy to learn, compared to other programming languages that require you to write code to perform specific tasks.

SQL is widely used for managing data in many different types of databases, including relational databases, data warehouses, and NoSQL databases. It is also used by many popular database management systems, such as MySQL, Microsoft SQL Server, Oracle, and PostgreSQL. This means that SQL is a highly in-demand skill for data professionals, and a solid understanding of SQL can be a valuable asset in many different fields.

Rename Command in SQL

In SQL, the RENAME command is used to change the name of a database object, such as a table, column, index, or view. The exact syntax of the RENAME command depends on the specific SQL database management system you are using, but here's a general example of how it can be used to rename a table:

RENAME TABLE old_table_name TO new_table_name;

Replace old_table_name with the current name of the table you want to rename and new_table_name with the desired new name for the table.

It is worth noting that the RENAME command is not a standard SQL command and may not be supported by all SQL database management systems. In some cases, you may need to use the ALTER TABLE command to achieve the same result, as I mentioned in my previous answer.

The syntax for renaming a column name in SQL depends on the specific SQL database you are using.

Here are the examples for renaming a column in some common SQL databases:

MySQL:

ALTER TABLE table_name
CHANGE COLUMN old_column_name new_column_name datatype;

SQL Server:

EXEC sp_rename 'table_name.old_column_name', 'new_column_name', 'COLUMN';

PostgreSQL:

ALTER TABLE table_name
RENAME COLUMN old_column_name TO new_column_name;

Oracle:

ALTER TABLE table_name
RENAME COLUMN old_column_name TO new_column_name;

Replace table_name with the actual name of your table, old_column_name with the current name of the column you want to rename, and new_column_name with the new name you want to give to the column.

Here's an example of renaming a column name in SQL using the ALTER TABLE statement:
-- create a sample table

CREATE TABLE employees (
id INT PRIMARY KEY,
  first_name VARCHAR(50),
  last_name VARCHAR(50),
department VARCHAR(50)
);

-- insert some sample data

INSERT INTO employees (id, first_name, last_name, department)
VALUES (1, 'John', 'Doe', 'Sales'),
       (2, 'Jane', 'Doe', 'Marketing'),
       (3, 'Jim', 'Smith', 'IT');

-- rename the "first_name" column to "firstname"

ALTER TABLE employees
RENAME COLUMN first_name TO firstname;

-- check if the column name was changed

SELECT *
FROM employees;

Output:

The output of the final SELECT statement should show the column first_name has been renamed to firstname.