Alter Table Charter For Free

ALTER TABLE table_name ADD INDEX index_name [index_type] (key_part,...) [index_option] .

The ALTER TABLE statement in SQL is used to add, remove, or modify columns in an existing table. The ALTER TABLE statement is also used to add and remove various constraints on existing tables.

- Column can't be deleted with alter command. - Column can't be renamed a column. - Column can't be added in between of the existing columns.

Use the ADD AUDIT clause with the ALTER TABLE command to include a table in selective row-level auditing. Use the ADD CONSTRAINT clause to specify a primary key, foreign key, referential, unique, or check constraint on a new or existing column or on a set of columns.

It is important to consider how schema changes will affect the data in a table. Adding an extra column to a table will add an extra column to all existing rows, just as it would in a spreadsheet. Deleting a column means all data in that column will be lost forever.

ALTER TABLE changes the structure of a table. For example, you can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself. You can also change characteristics such as the storage engine used for the table or the table comment.

Rename MySQL Column with the CHANGE Statement Enter the following command in your MySQL client shell 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 data type of the column or keep the existing one.