The ALTER TABLE statement in SQL is used to modify the structure of an existing table. It can be used to add, modify, or delete columns, constraints, and indexes.
Syntax:
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ALTER TABLE table_name [ADD/MODIFY/DROP COLUMN column_name datatype]; |
Example:
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ALTER TABLE cars ADD COLUMN manufacturer VARCHAR(255); |
In this example, the ALTER TABLE statement is used to add a new column manufacturer to the cars table. The column is of type VARCHAR(255), which means it can store string values up to 255 characters in length.
Note: The syntax for the ALTER TABLE statement may vary depending on the SQL database management system you are using.