Modifying a table in SQL CLI

16 Oct 2023

DatabaseManagement

In this blog post, we will explore the various ways to modify a table in the SQL Command Line Interface (CLI). We will cover renaming a table, adding or deleting columns, and modifying existing columns.

Renaming a Table
Adding or Deleting Columns
Modifying Existing Columns

Renaming a Table

To rename a table in SQL CLI, we can use the ALTER TABLE statement along with the RENAME TO clause. Here’s an example:

ALTER TABLE old_table_name RENAME TO new_table_name;

Make sure to 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.

Adding or Deleting Columns

To add or delete columns in a table, again we use the ALTER TABLE statement. To add a new column, we use the ADD COLUMN clause, and to delete a column, we use the DROP COLUMN clause. Here are some examples:

Adding a Column:

ALTER TABLE table_name ADD COLUMN column_name column_datatype;

Replace table_name with the name of the table where you want to add the column, column_name with the name of the new column, and column_datatype with the datatype for the new column.

Deleting a Column:

ALTER TABLE table_name DROP COLUMN column_name;

In this case, replace table_name with the name of the table from which you want to delete the column, and column_name with the name of the column to be deleted.

Modifying Existing Columns

To modify an existing column in a table, we can use the ALTER TABLE statement along with the ALTER COLUMN clause. Here’s an example:

ALTER TABLE table_name ALTER COLUMN column_name SET DATATYPE new_datatype;

Replace table_name with the name of the table containing the column, column_name with the name of the column you want to modify, and new_datatype with the desired new datatype for the column.

Conclusion

Modifying a table in SQL CLI can be done easily using the ALTER TABLE statement along with the appropriate clauses such as RENAME TO, ADD COLUMN, DROP COLUMN, and ALTER COLUMN. This flexibility allows us to make changes to our database structure as per our requirements.

If you have any further questions or need more information, please refer to the documentation of your specific SQL CLI or consult relevant online resources.

#SQL #DatabaseManagement

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