The command to modify the table structure in sql is

The command in SQL to modify the table structure is ALTER TABLE, which supports the following operations: Use ADD COLUMN to add new columns, use DROP COLUMN to delete existing columns, use ALTER COLUMN to modify existing column attributes, and use ADD FOREIGN KEY to add foreign key constraints. Use DROP FOREIGN KEY to delete foreign key constraints. Use RENAME TABLE to modify the table name

Commands to modify the table structure in SQL

In SQL, you can use the ALTER TABLE statement to modify the table structure. The ALTER TABLE statement supports various modification operations on the table, including:

Add columns

Use the ADD COLUMN sub Sentence to add a new column:

<code class="sql">ALTER TABLE table_name ADD COLUMN new_column_name data_type;</code>

Delete a column

Use the DROP COLUMN clause to delete an existing column:

<code class="sql">ALTER TABLE table_name DROP COLUMN column_name;</code>

Modify columns

Use the ALTER COLUMN clause to modify the name, data type, or other properties of an existing column:

<code class="sql">ALTER TABLE table_name ALTER COLUMN column_name new_column_name data_type;</code>

Add a foreign key

Use the ADD FOREIGN KEY clause to add a foreign key constraint:

<code class="sql">ALTER TABLE table_name ADD FOREIGN KEY (foreign_key_column) REFERENCES referenced_table(referenced_column);</code>

Delete the foreign key

UseDROP FOREIGN KEY clause deletes existing foreign key constraints:

<code class="sql">ALTER TABLE table_name DROP FOREIGN KEY foreign_key_name;</code>

Modify table name

Use RENAME TABLE clause Modify table name:

<code class="sql">RENAME TABLE old_table_name TO new_table_name;</code>

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