What is the purpose of the ALTER TABLE statement in SQL?

The “Alter table” statement in SQL is used to modify the structure of a database table, allowing for the following functions to be achieved:

1. Add a new column to the table.
2. Alter the data type or attributes of an existing column.
3. Remove a column from the table.
4. Rename the columns in the table.
5. Add or remove primary keys, foreign keys, or indexes from a table.
6. Change the engine type of the table.
7. Change the character set or collation rules of the table.

In conclusion, the “alter table” statement can assist database administrators in flexibly managing the structure of database tables, making adjustments and optimizations according to actual needs.