How To Change The Name Of A Variable In Mysql

Introduction

MySQL provides a dynamic environment that enables you to alter database items with a few basic commands. By learning how to use various statements, you can manage your databases with ease.

This tutorial contains all the commands needed to rename a column in a MySQL database.

Prerequisites

• A functional example of MySQL
• A user with Modify privileges on the MySQL server

Rename MySQL Column with ALTER Table Command

Change TABLE is an essential control used to change the structure of a MySQL table. You tin can use it to add or delete columns, modify the type of data inside the columns, and even rename entire databases. The office that concerns the states the near is how to utilize ALTER TABLE to rename a cavalcade.

Statements give united states of america boosted command over the renaming procedure. The RENAME Column and Modify statements both allow for the names of existing columns to exist contradistinct. The difference is that the CHANGE clause tin also be used to modify the data types of a column.

Rename MySQL Column with the RENAME Statement

The simplest fashion to rename a cavalcade is to use the Modify Tabular array control with the RENAME Cavalcade clause. This clause is available since MySQL version viii.0.

Permit's illustrate its simple syntax. To change a column proper noun, enter the post-obit argument in your MySQL crush:

          ALTER TABLE table_name RENAME Column old_column_name TO new_column_name;        

Supervene upon table_name , old_column_name , and new_column_name with your table and column names. Keep in listen that you cannot rename a column to a name that already exists in the table.

For instance, to modify the column id into employee_id in the table employees, you would run:

          ALTER Tabular array employees RENAME COLUMN id TO employ_id;        

The RENAME Column argument tin but be used to rename a column. If you demand additional functions, such equally changing the information definition, or position of a column, employ the Modify clause instead.

Note: The give-and-take Cavalcade is obligatory for the Change Table RENAME COLUMN command. Alter TABLE RENAME is the existing syntax to rename the unabridged table.

Rename MySQL Column with the CHANGE Statement

The Alter clause offers important additions to the renaming process. Information technology can be used to rename a column and change the data type of that cavalcade with the same command.

Enter the post-obit control in your MySQL client crush to change the name of the column and its definition:

          ALTER TABLE table_name CHANGE old_column_name new_col_name Data Type;        

You can change the information type of the cavalcade or keep the existing one. In both cases you take to specify the data type every bit the chemical element is mandatory.

For example, to change the column id into employee_id which has the data type VARCHAR(25) in the table employees, you lot would run:

          ALTER Table employees CHANGE id employ_id VARCHAR(25);        

Note: If y'all don't know the information blazon of the column you are renaming, check the structure of the table and the column definition using the DESCRIBE statement: Depict table_name; .

Boosted Options

Yous can utilise boosted options to further dispense table columns. The CHANGE also allows you to place the column in a unlike position in the table past using the optional First | AFTER column_name clause. For example:

          ALTER Table table_name CHANGE old_column_name new_col_name Data Type AFTER column_x;        

With the control higher up you can changed the name of the column, changed the data blazon to y_data_type , and positioned the cavalcade after column_x .

Rename Multiple MySQL Columns

MySQL allows you to rename multiple columns with a single command. This pick is possible with the RENAME and the Alter statement.

To modify the names of multiple columns using the RENAME Column clause, utilize the syntax:

          Alter Table table_name  RENAME Column old_column_name1 TO new_col_name1, RENAME COLUMN old_column_name2 TO new_col_name2, RENAME COLUMN old_column_name3 TO new_col_name3;        

To change the names of multiple columns using the Alter clause, use the syntax:

          ALTER TABLE table_name  Change old_column_name1 new_col_name1 Data Type, Alter old_column_name2 new_col_name2 Data Type, Modify old_column_name3 new_col_name3 Information Blazon;        

Conclusion

You lot have successfully renamed an existing column in your MySQL database. This article has offered ii options and provided the necessary commands. Understanding the essential ALTER TABLE argument is a precondition for exploring more circuitous expressions.

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Source: https://phoenixnap.com/kb/how-to-rename-column-mysql

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