What is ALTER command explain?

What is the ALTER command?

The ALTER command is a DDL command to modify the structure of existing tables in the database by adding, modifying, renaming, or dropping columns and constraints. You can add columns, rename columns, delete columns, or change the data type of columns using the ALTER command.

What is an ALTER command explain with example?

ALTER TABLE table_name ADD column_name datatype; The basic syntax of an ALTER TABLE command to DROP COLUMN in an existing table is as follows. ALTER TABLE table_name DROP COLUMN column_name; The basic syntax of an ALTER TABLE command to change the DATA TYPE of a column in a table is as follows.

Where is ALTER command used?

alter command is used for altering the table structure, such as,1to add a column to existing table.2to rename any existing column.3to change datatype of any column or to modify its size.4to drop a column from the table.

What is ALTER in database?

ALTER DATABASE enables you to change the overall characteristics of a database. These characteristics are stored in the data dictionary. This statement requires the ALTER privilege on the database. ALTER SCHEMA is a synonym for ALTER DATABASE .