# Alter and Drop

The drop command will remove a table from the database schema.

```
drop table table_name
```

The alter command is used to add, delete, or modify columns in an existing table.

`alter table r add column column_name data_type`

`alter table r drop column column_name`

`alter table r alter column column_name data_type`

`alter table r modify [column] column_name data_type`